Search

Abstract Background Hematophagy is a common trait of insect vectors of disease. Extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. Studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. The mosquito Aedes aegypti (Diptera, Culicidae), a vector of Dengue viruses, Yellow Fever Virus (YFV) and Chikungunya virus (CV), is the subject of this study to look at genome-wide changes in gene expression following a blood meal. Results Transcriptional changes that follow a blood meal in Ae. aegypti females were explored using RNA-seq technology. Over 30% of more than 18,000 investigated transcripts accumulate differentially in mosquitoes at five hours after a blood meal when compared to those fed only on sugar. Forty transcripts accumulate only in blood-fed mosquitoes. The list of regulated transcripts correlates with an enhancement of digestive activity and a suppression of environmental stimuli perception and innate immunity. The alignment of more than 65 million high-quality short reads to the Ae. aegypti reference genome permitted the refinement of the current annotation of transcript boundaries, as well as the discovery of novel transcripts, exons and splicing variants. Cis-regulatory elements (CRE) and cis-regulatory modules (CRM) enriched significantly at the 5'end flanking sequences of blood meal-regulated genes were identified. Conclusions This study provides the first global view of the changes in transcript accumulation elicited by a blood meal in Ae. aegypti females. This information permitted the identification of classes of potentially co-regulated genes and a description of biochemical and physiological events that occur immediately after blood feeding. The data presented here serve as a basis for novel vector control and pathogen transmission-blocking strategies including those in which the vectors are modified genetically to express anti-pathogen effector molecules.

Abstract Background The most abundant family of insect cuticular proteins, the CPR family, is recognized by the R&R Consensus, a domain of about 64 amino acids that binds to chitin and is present throughout arthropods. Several species have now been shown to have more than 100 CPR genes, inviting speculation as to the functional importance of this large number and diversity. Results We have identified 156 genes in Anopheles gambiae that code for putative cuticular proteins in this CPR family, over 1% of the total number of predicted genes in this species. Annotation was verified using several criteria including identification of TATA boxes, INRs, and DPEs plus support from proteomic and gene expression analyses. Two previously recognized CPR classes, RR-1 and RR-2, form separate, well-supported clades with the exception of a small set of genes with long branches whose relationships are poorly resolved. Several of these outliers have clear orthologs in other species. Although both clades are under purifying selection, the RR-1 variant of the R&R Consensus is evolving at twice the rate of the RR-2 variant and is structurally more labile. In contrast, the regions flanking the R&R Consensus have diversified in amino-acid composition to a much greater extent in RR-2 genes compared with RR-1 genes. Many genes are found in compact tandem arrays that may include similar or dissimilar genes but always include just one of the two classes. Tandem arrays of RR-2 genes frequently contain subsets of genes coding for highly similar proteins (sequence clusters). Properties of the proteins indicated that each cluster may serve a distinct function in the cuticle. Conclusion The complete annotation of this large gene family provides insight on the mechanisms of gene family evolution and clues about the need for so many CPR genes. These data also should assist annotation of other Anopheles genes.

We present an application of the latest UCL‐AGA magnetodisc model (MDISC) to the study of the magnetic and plasma conditions in the near‐Ganymede space. By doing this, we provide a comparison with measurements from Juno's most recent flyby of the Jovian moon, perijove 34 (PJ34). We find good agreement between the model results and the magnetometer data, pointing toward a hot plasma index value Kh= ${K}_{h}=$ (2.719± $\pm $0.024)× ${\times} $107 Pa m T−1 and an effective magnetodisc radius rmax= ${r}_{\text{max}}=$ (79.5± $\pm $1.1) Jupiter radii for the Jovian magnetosphere, for the duration of the trajectory, suggesting a configuration with middling levels of expansion. We also predict the plasma conditions observed by Juno during the same flight‐path, as well as the typical conditions over the orbit of Ganymede, with the magnetic and hot plasma pressures assuming dominant roles. Finally, these results are compared with functional fits of a compilation of Galileo flyby data obtained in the vicinity of Ganymede's orbit, suggesting Juno experienced somewhat similar conditions, despite a systematic overestimation in magnetic field intensity in the near‐Ganymede space. Plain Language Summary: Being the largest moon in the Solar system and the only one with its own magnetic field, Ganymede presents a unique target for magnetospheric interaction studies. Although much weaker than the Jovian magnetic field surrounding it, Ganymede's field is strong enough to carve a small region in space, called a magnetosphere, which is itself contained within Jupiter's own magnetosphere. The interplay between these two structures gives rise to numerous phenomena that can affect the near‐Ganymede environment. There is also evidence for an additional inductive contribution resulting from the interaction of Jupiter's time varying magnetic field and a possible subsurface ocean. By understanding how the different field contributions affect the overarching environment around Ganymede, we can extract valuable information about the moon's atmosphere, internal composition and its relation with the Jovian environment. In this study we compare our model's predictions with data gathered by Juno during one of its orbits around Jupiter, which also included a Ganymede flyby, showing good agreement between the two. We then predict the plasma conditions the spacecraft encountered during the same trajectory, as well as over Ganymede's orbit, highlighting the main pressure contributions and how these vary according to the rotational phase of Jupiter's magnetic pole. Key Points: Strict constraints on magnetospheric field and plasma configuration can be inferred from magnetic field observations aloneJupiter's rotation and the position of Ganymede relative to the plasma sheet drive the magnetic and plasma environments surrounding the moonMagnetic and hot plasma pressures assume the dominant roles in dictating the plasma environment near Ganymede [ABSTRACT FROM AUTHOR]

The magnetospheric cusp connects the planetary magnetic field to interplanetary space, offering opportunities for charged particles to precipitate to or escape from the planet. Terrestrial cusps are typically found near noon local time, but the characteristics of the Jovian cusp are unknown. Here we show direct evidence of Jovian cusps using datasets from multiple instruments onboard Juno spacecraft. We find that the cusps of Jupiter are in the dusk sector, which is contradicting Earth-based predictions of a near-noon location. Nevertheless, the characteristics of charged particles in the Jovian cusps resemble terrestrial and Saturnian cusps, implying similar cusp microphysics exist across different planets. These results demonstrate that while the basic physical processes may operate similarly to those at Earth, Jupiter's rapid rotation and its location in the heliosphere can dramatically change the configuration of the cusp. This work provides useful insights into the fundamental consequences of star-planet interactions, highlighting how planetary environments and rotational dynamics influence magnetospheric structures. Jovian cusps are not well-known due to limited observations. Here, the authors show that the characteristics of charged particles in the Jovian cusps are similar to those of the Earth and Saturn cusps, and Jupiter's polar cusp is located in the dusk-side sector, contradicting Earth-based predictions of a near-noon location. [ABSTRACT FROM AUTHOR]

In the Jovian magnetosphere, quasi‐periodic phenomena, with quasi‐periods on the order of 10–60 min, are frequently identified using different data sets. These pulsations are a branch of ultra‐low frequency (ULF) waves, which are believed to play a crucial role in driving the energy circulation within Jupiter's magnetosphere. In this study, we utilize magnetic field data collected by Juno between 2016 and 2022 to perform a comprehensive global statistical analysis of the spatial distribution and periodic characteristics of ULF waves in the Jovian magnetosphere. Our findings reveal distinct periodic features observed at different latitudes and distances, providing valuable insights into the generation mechanisms of ULF waves. Furthermore, we establish a close relationship between the presence of these ULF wave fluctuations and the magnetospheric state, such as under conditions of solar wind compression. By combining contemporaneous ultraviolet aurora observations from the Hubble Space Telescope (HST) and magnetic field data obtained by Juno, we have discovered that the compressed magnetospheres exhibit more pronounced ULF waves and enhanced auroral activity. These results provide a global picture of the distribution, implying potential generation of ULF waves in the Jovian magnetosphere, and shedding light on the processes behind the 10–60‐min energy releases. Plain Language Summary: In the Jovian system, there are patterns of magnetic waves with periods of 10–60 min. These waves are part of a larger category called ultra‐low‐frequency waves and play an important role in how energy moves around Jupiter. Here, we study these waves using data collected by the Juno spacecraft from 2016 to 2022, investigating where these waves occur and how often they occur. The waves are different depending on the location and distance from Jupiter, which gives us clues about how they are created. These waves also appear to be more common when Jupiter's magnetic field is compressed by the solar wind. We have also combined data from the Hubble Space Telescope and Juno, and found that the compressed magnetic field leads to more of these waves and stronger auroras on Jupiter. This research helps us to understand how these 10–60‐min bursts of energy work in Jupiter's magnetosphere. Key Points: We investigate the spatial distribution and periodic characteristics of ultra‐low frequency (ULF) waves in the Jovian magnetosphereWe examine and compare the occurrence rate of ULF waves under different solar wind compression statesThe connection between ULF waves and auroral morphology provides key constraints on wave generation mechanisms [ABSTRACT FROM AUTHOR]

Abstract Background Hematophagy is a common trait of insect vectors of disease. Extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. Studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. The mosquito Aedes aegypti (Diptera, Culicidae), a vector of Dengue viruses, Yellow Fever Virus (YFV) and Chikungunya virus (CV), is the subject of this study to look at genome-wide changes in gene expression following a blood meal. Results Transcriptional changes that follow a blood meal in Ae. aegypti females were explored using RNA-seq technology. Over 30% of more than 18,000 investigated transcripts accumulate differentially in mosquitoes at five hours after a blood meal when compared to those fed only on sugar. Forty transcripts accumulate only in blood-fed mosquitoes. The list of regulated transcripts correlates with an enhancement of digestive activity and a suppression of environmental stimuli perception and innate immunity. The alignment of more than 65 million high-quality short reads to the Ae. aegypti reference genome permitted the refinement of the current annotation of transcript boundaries, as well as the discovery of novel transcripts, exons and splicing variants. Cis-regulatory elements (CRE) and cis-regulatory modules (CRM) enriched significantly at the 5'end flanking sequences of blood meal-regulated genes were identified. Conclusions This study provides the first global view of the changes in transcript accumulation elicited by a blood meal in Ae. aegypti females. This information permitted the identification of classes of potentially co-regulated genes and a description of biochemical and physiological events that occur immediately after blood feeding. The data presented here serve as a basis for novel vector control and pathogen transmission-blocking strategies including those in which the vectors are modified genetically to express anti-pathogen effector molecules.

The Jovian magnetosphere is highly dynamic, influenced by both solar wind and internal processes associated with the rapid planetary rotation and Io's volcanic activities. Accompanying the mass and energy circulations driven by the magnetospheric dynamics, the magnetic configuration also changes dramatically. One of the crucial parameters to characterize the magnetic configuration is magnetic field line curvature (FLC), which generally describes how stretched the field line is. The curvature is pivotal to influence particle behaviors, for example, pitch angle scattering which may lead to auroral particle precipitation. In this work, a method is proposed to investigate the real‐time magnetic FLC in Jovian current sheet using the magnetic field data from the Juno spacecraft. The results indicate that the FLC scattering of ions and relativistic electrons are common in Jovian magnetosphere, providing a crucial insight to understand the particle behaviors. Plain Language Summary: Both the Earth and the Jupiter have intrinsic magnetic field. When the planetary magnetic field interacts with the solar wind, a region called magnetosphere is formed. Particle behaviors in different planetary systems are different, due to the different magnetospheric dynamics. The curvature of magnetic field, describing the stretch level of a magnetic field line, is a basic parameter to describe a planetary space system, and it can significantly influence particle behaviors, for example, to scatter the magnetospheric particles to planetary atmosphere, causing auroral emissions. In this work, we proposed a method to calculate the magnetic field line curvature (FLC) near the equatorial plane inside the Jupiter's magnetosphere using Juno data set, for the first time to provide a global picture on the magnetic FLC. By comparing with the radius of particles' gyration motions, we suggest that ions and electrons can be strongly scattered by the magnetic FLC. We believe that the results in this study provide useful information on the different particle behaviors between the terrestrial system and the Jovian system. Key Points: We proposed a method to investigate the magnetic field line curvature (FLC) in Jupiter's current sheet using data from Juno data set50 events are selected by specific criteria. The magnetic FLC and different particles' Larmor radius are investigatedThe FLC will scatter ions and relativistic electrons as a potential cause of auroral precipitation [ABSTRACT FROM AUTHOR]

On 15 September 2021, Chandra carried out a 40‐hr (∼4 jovian rotations) observation as part of its longest planetary campaign to study the drivers of jovian X‐ray aurora that may be linked to ultra‐low frequency (ULF) wave activity. During this time, Juno's orbit had taken the spacecraft into Jupiter's dusk magnetosphere. Here is believed to be the most probable location of ULF waves propagating along jovian magnetic field lines that drive the X‐ray auroral emissions. This is the first time that this region has been observed by an orbiter since Galileo >20 years ago, and never before has there been contemporaneous in situ and X‐ray observations. A 1D solar wind propagation model identifies a compression event near the midpoint of the 40‐hr observation window. The influence of a compression is confirmed when comparing the measured magnetic field in the dusk lobes of the magnetotail from Juno MAG data against a baseline lobe field model. Data from the Juno Waves instrument also show activation of broadband kilometric (bKOM) emissions during the arrival of the shock, a feature that has previously been observed during compression events. Therefore this is the first time we can fully analyze the morphological variability during the evolution of a shock. Wavelet transforms and Rayleigh testing are used to search for statistically significant quasi‐periodic pulsations (QPPs) of the X‐ray emissions in the data set, and find significant QPPs with periods of 25–26 min for the northern auroral X‐rays. Key Points: We compare a 40‐hr Chandra observation of Jupiter's X‐ray aurora with in situ Juno measurements and a 1‐D solar wind propagation modelWe find statistically significant quasi‐periodic pulsation with a ∼25 min period likely linked to the arrival of a solar wind compressionUsing Juno MAG data form the dusk tail lobes, we infer the state of compression/loading of the magnetosphere [ABSTRACT FROM AUTHOR]

We define the spatial clustering of X‐rays within Jupiter's northern auroral regions by classifying their distributions into "X‐ray auroral structures." Using data from Chandra during Juno's main mission observations (24 May 2016 to 8 September 2019), we define five X‐ray structures based on their ionospheric location and calculate the distribution of auroral photons. The morphology and ionospheric location of these structures allow us to explore the possibility of numerous X‐ray auroral magnetospheric drivers. We compare these distributions to Hubble Space Telescope (HST) and Juno (Waves and MAG) data, and a 1D solar wind propagation model to infer the state of Jupiter's magnetosphere. Our results suggest that the five sub‐classes of "X‐ray structures" fall under two broad morphologies: fully polar and low latitude emissions. Visibility modeling of each structure suggests the non‐uniformity of the photon distributions across the Chandra intervals are likely associated with the switching on/off of magnetospheric drivers as opposed to geometrical effects. The combination of ultraviolet (UV) and X‐ray morphological structures is a powerful tool to elucidate the behavior of both electrons and ions and their link to solar wind/magnetospheric conditions in the absence of an upstream solar monitor. Although much work is still needed to progress the use of X‐ray morphology as a diagnostic tool, we set the foundations for future studies to continue this vital research. Plain Language Summary: The mechanism that allows precipitation of ions into Jupiter's atmosphere and generate pulsed X‐ray auroral emissions is still under debate today. Previous studies have linked this driver to possible activity in Jupiter's outer magnetosphere (the interface between the solar wind and Jupiter) and have observed the emissions to exhibit variable behavior. More recent studies have suggested a wide range of physical phenomena causing these emissions. Here we explore this idea in more detail by introducing five "X‐ray auroral structures" that map to different regions in the Jovian system. Using data from the Chandra X‐ray Observatory during Juno's main mission allows us to calculate the distribution of X‐rays from Jupiter's northern auroral region. We compare our X‐ray results with the ultraviolet emissions ("UV auroral families") observed from simultaneous Hubble Space Telescope (HST) data and infer the conditions at Jupiter using models and Juno observations. These "X‐ray structures" provide us with many ways to observe variable behavior and provide a possible tool to monitor the solar wind conditions, when used in tandem with the HST "UV auroral families." Key Points: We present the morphology of new "X‐ray auroral structures," observed on Jupiter via Chandra's high spatial resolution cameraWe show that non‐uniform auroral photon distributions are likely from "switching on/off" of auroral driver(s) opposed to planetary tiltWe show that combination of X‐ray and ultraviolet (UV) "auroral families" may be a useful proxy to determine the magnetospheric conditions at Jupiter [ABSTRACT FROM AUTHOR]

Magnetic Dipolarization, a hallmark indicator of the formation of field‐aligned currents, plays a crucial role in the energy dissipative processes that occur within planetary magnetospheres. Saturn's magnetic dipolarization was found to recur after one planetary rotation, suggesting a potential correlation with the corotating current systems. The observation of enhanced Energetic Neutral Atoms (ENA) within Saturn's inner magnetosphere serves as a diagnostic tool, revealing the existence of a rotating, dynamic Partial Ring Current (PRC) system. By utilizing multiple datasets from Cassini, this study advances the understanding of the interrelationship between ENA emission and magnetic dipolarization. Our results suggest the possibility of a coupling between the PRC system revealed by the ENA emission and magnetic dipolarization. Furthermore, a temporal correlation was found between the ENA emissions and two distinct radio emissions. This study discusses potential causal relationships among these phenomena and first time proposes a global unified physical picture. Plain Language Summary: Energy dissipation and circulation are the core of the space plasma field, which shows different typical features at different planets. Unlike the solar wind‐driven terrestrial magnetosphere, the giant planetary magnetospheric processes are strongly controlled by internal processes, and show strong rotational modulation in the in situ and remote sensing measurements. The rotation modulation of the observations in Saturn's magnetosphere may lead to challenges in the interpretation of data. The observed variations in data are a combination of spatial and temporal variations. In this study, we analyzed the multiple datasets from Cassini to formulate a uniform picture of the periodic variations including magnetic field variation, rotating hot plasma cloud, and radio emissions. We propose that the corotating current system could potentially connect all observed phenomena. Key Points: Recurrent magnetic dipolarization and Energetic Neutral Atoms (ENA) enhancement are correlatedThe SKR and 20 kHz narrow band emissions are likely connected to the rotating hot plasma cloud revealed by ENA observationPeriodic enhancements of SKR are concurrent but slightly time‐lag/lead the recurrent magnetic dipolarizations [ABSTRACT FROM AUTHOR]

Jupiter's auroral emission is a spectacular phenomenon that provides insight into energy release processes related to the coupling of its magnetosphere and ionosphere. This energy release is influenced by solar wind conditions. Using joint observations from Juno and the Hubble Space Telescope (HST), we statistically investigate the relationship between auroral power and current sheet variations under different solar wind conditions. In this study, we reveal that during global main auroral brightening events that are closely connected to solar wind compressions, the dawn side current sheet is substantially thinner than during times when a quiet auroral morphology is present. Furthermore, the total current intensity in the current sheet is found to increase under solar wind compression conditions compared to the quiet period. These findings provide important observational evidence for how magnetospheric dynamics driven by solar wind behavior affect auroral activity, deepening our understanding of the coupling between Jupiter's magnetosphere and ionosphere. Plain Language Summary: Jupiter, the largest planet in our solar system, has a fascinating and powerful auroral emission that can help us understand the interactions between its magnetic field and the charged particles in its atmosphere. These auroral emissions are influenced by solar wind conditions, which are streams of charged particles coming from the Sun. In this study, we used observations from the Juno spacecraft and the Hubble Space Telescope to investigate the relationship between Jupiter's auroral emissions and changes in the planet's magnetic field. We found that during periods of increased solar wind pressure, the magnetic field layer, known as the current sheet, becomes thinner compared to times when the aurora is quiet. These findings offer valuable evidence of how Jupiter's magnetic field is affected by solar wind behavior and improve our understanding of the relationship between the planet's magnetic field and its aurora. This research helps us better comprehend the complex processes occurring in Jupiter's magnetosphere and can potentially enhance our knowledge of similar phenomena occurring on other planets. Key Points: The features of the current sheet in Jupiter's dawnside magnetosphere are highly relevant to auroral contextsDuring a solar wind compression event, the dawnside current sheet becomes substantially thinner than during quiet timesThe total current intensity of the current sheet is much higher during solar wind compression events than the quiet times [ABSTRACT FROM AUTHOR]

Jupiter's disc is bright in X-rays as H2 molecules in the atmosphere are very effective at scattering solar X-rays. K-shell fluorescence from carbon atoms in atmospheric methane is thought to also provide a minor contribution. XMM–Newton has now observed Jupiter over a span of nearly two solar cycles from 2003 to 2021, offering the opportunity to determine whether Jupiter's disc emissions are driven by solar activity or not. We compare the count rates of X-rays of energies 0.2–10.0, 0.2–2.0, 2.1–5.0, and 5.1–10.0 keV from the planet's equatorial region, with the sunspot number and F10.7 adjusted solar radio flux. The respective Pearson's correlation coefficients for both are 0.88/0.84, 0.86/0.83, 0.40/0.34, and 0.29/0.22 for each energy demonstrating that the low-energy X-ray disc emissions are indeed controlled by the Sun's activity. This relationship is less clear for the higher energy emissions, raising questions around the source of these emissions. [ABSTRACT FROM AUTHOR]

Periodic variations are widely identified in the Jovian system, varying from 10 s of seconds to several days or even longer. These processes are strongly influenced by solar wind conditions, planetary rotation and Io's volcanic activity. Ultralow‐frequency (ULF) waves at 10 s of minutes, which are the typical time scale of field‐line resonance, are considered as a crucial process in driving the Jovian energy circulation. The longer time‐scale periodicities are likely associated with global mass circulation. In this study, we focus on multihour variations of the ULF wave energy, which are difficult to identify within the magnetosphere due to the rapid planetary rotation modulation. Using the magnetic field observations from Juno and Galileo in Jupiter's magnetosheath, we found multiple significant multihour periodicities, widely distributed from 2 to 10 hr, peaked at different values from case to case. The most common periodicities were between 3 and 5 hr, existing in both the dawn and dusk sides. These common periodicities are likely associated with the energy transport from the inside to the magnetosheath. Plain Language Summary: Periodicities, as detected in aurora, particles, waves, etc., widely exist in the Jovian system. The periodic variations are key signatures to assess theoretical hypotheses, and the coherence between the periodicities in different types of observations can be a crucial constraint to reveal physical causality. Jupiter's magnetic axis is about 10 degrees offset from the rotation axis, resulting in a periodic vibration of the magnetosphere. A spacecraft traveling in Jupiter's magnetospheric space would persistently detect rapid variations of the magnetic field every several hours, and the variation feature depends on the relative location to the magnetic equator and the dynamic magnetospheric processes. Therefore, the investigation of hourly variation of the Jovian magnetosphere is highly challenging due to the strong mixture of spatial and temporal effects. To overcome this difficulty, we analyze magnetic field and plasma wave data in Jupiter's magnetosheath, where the planetary rotation induced spatial variations no longer exist. Many multihour periodicities are identified, which are believed to be consequences of compressions from the rotating magnetospheric plasma to the magnetopause. Key Points: We systematically investigate the hourly periodic variations in Jupiter's magnetosheath by analyzing magnetic field dataPeriodicities from 2 to 10 hr are widely identified, where results of periodic analysis change from time to timeSimilar hourly periodicities were identified in both dawn and dusk sides [ABSTRACT FROM AUTHOR]

We present a statistical study of Jupiter's disk X‐ray emissions using 19 years of Chandra X‐Ray Observatory (CXO) observations. Previous work has suggested that these emissions are consistent with solar X‐rays elastically scattered from Jupiter's upper atmosphere. We showcase a new pulse invariant (PI) filtering method that minimizes instrumental effects which may produce unphysical trends in photon counts across the nearly two‐decade span of the observations. We compare the CXO results with solar X‐ray flux data from the Geostationary Operational Environmental Satellites X‐ray Sensor for the wavelength band 1–8 Å (long channel), to quantify the correlation between solar activity and Jovian disk counts. We find a statistically significant Pearson's Correlation Coefficient of 0.9, which confirms that emitted Jovian disk X‐rays are predominantly governed by solar activity. We also utilize the high spatial resolution of the High Resolution Camera Instrument on‐board the CXO to map the disk photons to their positions on Jupiter's surface. Voronoi tessellation diagrams were constructed with the Juno Reference Model through Perijove 9 internal field model overlaid to identify any spatial preference of equatorial photons. After accounting for area and scattering across the curved surface of the planet, we find a preference of Jovian disk emission at 2–3.5 Gauss surface magnetic field strength. This suggests that a portion of the disk X‐rays may be linked to processes other than solar scattering: the spatial preference associated with magnetic field strength may imply increased precipitation from the radiation belts, as previously postulated. Plain Language Summary: The X‐ray radiation that Jupiter emits from the region around the equator, or disk region, behaves differently to the auroral X‐ray emissions (northern and southern lights). It has long been believed that these emissions are mainly caused by solar X‐rays that reflect off of the planet's upper atmosphere, lighting up the disk. These high‐energy X‐ray emissions can be observed by the Earth‐orbiting Chandra X‐ray Observatory (CXO). There have been multiple X‐ray campaigns of Jupiter using Chandra from 2000 to 2019. Here, we compare this data with solar X‐ray data from the Geostationary Operational Environmental Satellites and identify a strong link between the disk X‐ray emissions and solar activity. The High Resolution Camera on‐board the CXO also enables us to pinpoint the location of these emissions, which we incorporate with magnetic field data from NASA's Juno to provide a more complete picture of the conditions at Jupiter's upper atmosphere. Key Points: We present a statistical study of Jovian disk X‐rays from 19 years worth of Chandra data showing a strong correlation with solar X‐ray fluxJovian disk emissions are predominantly governed by solar activity. Pearson's Correlation Coefficient of 0.9 found between the dataAnalysis of spatial morphology of the disk emissions reveals preference of disk emission at 2–3.5 Gauss magnetic field strength [ABSTRACT FROM AUTHOR]

Jupiter displays the most powerful auroral emissions in our solar system, which result from strong energy dissipation in Jupiter's surrounding space environment. Although mass and energy in Jupiter's magnetosphere mostly come from the innermost Galilean moon Io's volcanic activity and Jupiter's rotation, solar wind perturbations can play crucial roles in releasing magnetospheric energy. The systematic response of the aurora to a solar wind compression remains poorly understood because of timing uncertainties. Here we report the analysis of a set of auroral images from the Hubble Space Telescope with contemporaneous in situ magnetopause detections from Juno, allowing for a more direct comparison. By analyzing the dawn side main auroral emission, we distinguish two non-mutually exclusive types of auroral enhancements: auroral dawn storm (ADS) featured with latitudinal extension in limited longitudes, and a long-lasting main auroral brightening with limited extension in latitudes while extending over a large longitude range. Only the latter systematically appears under a compressed magnetopause, while the dawn storms could occur whatever the state of the magnetopause. The results could provide important constraints to improve theoretical models and numerical simulations. During expanded magnetopause conditions, Jupiter's aurora displayed either quiet or dawn storm morphology. The result is consistent with recent discovery of the initiation of ADSs in midnight and post-midnight, possibly driven by magnetic reconnection plasma instabilities in night magnetotail. Our results show that some typical auroral morphologies could be used as a diagnostic of solar wind conditions at Jupiter. [ABSTRACT FROM AUTHOR]

Two series of tests with different depth wood I-joists were conducted to study the effects of circular and square web openings and the placement of steel angle retrofits at openings. Finite-element analysis of all test configurations was used to improve understanding of how web openings and retrofits affect the stiffness, stress distributions around openings, and ultimate failure mechanisms. Test results show failure loads well above prescribed design loads; however, the presence of web openings affected the type of failure modes. Control joists failed at the tension flange, whereas joists with web openings failed in shear through web openings or by means directly attributable to the presence of an opening. Ultimate capacity and stiffness was generally reduced by the presence of a web opening, with openings located closer to high shear areas producing worse results. Square web openings lowered the ultimate capacity approximately 10% more than circular openings when located at the same location. Steel angle retrofits improved capacity if an adequate retrofit length was used to redistribute stress concentrations. Finite-element models accurately predicted decreases in stiffness due to web openings; however, the models predict an improvement in stiffness due to the presence of steel retrofits that was not ascertained in experimental results. DOI: 10.1061/(ASCE)ST.1943-541X.0000013 CE Database subject headings: Wood; Joists; Webs; Finite element method; Rehabilitation; Experimentation; Openings.

We present 14 simultaneous Chandra X‐ray Observatory (CXO)‐Hubble Space Telescope (HST) observations of Jupiter's Northern X‐ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X‐ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST observations have shown that very little UV emission is produced by the DPR. We find that the DPR also produces very few X‐ray photons. For all 14 observations, the low level of X‐ray emission from the DPR is consistent (within 2‐standard deviations) with scattered solar emission and/or photons spread by Chandra's Point Spread Function from known X‐ray‐bright regions. We therefore conclude that for these 14 observations the DPR produced no statistically significant detectable X‐ray signature. Plain Language Summary: Jupiter produces the most powerful ultraviolet (UV) and X‐ray aurorae in the solar system. While the UV and X‐ray aurora of the planet have each been explored independently, previous work exploring the spatial connection between Jupiter's X‐ray and UV aurorae was limited to a single simultaneous Chandra X‐ray Observatory (CXO) and Hubble Space Telescope (HST) observation from 2003. Since 2016, the arrival of the Juno spacecraft at Jupiter has led to extensive observing campaigns with CXO and HST, resulting in many new simultaneous X‐ray‐UV observations. Here, we present the analysis of 14 simultaneous CXO and HST observations of Jupiter's Northern aurorae from 2016 to 2019. While much of the emission from these bright aurorae is dynamic, there is one region that is dim for all 14 observations: Jupiter's dark polar region. Previous observations of this region have shown that it produces very little UV light. However, the extent to which X‐ray light is produced by the region remained unexplored and could provide the key to identifying why the region is so dark and what this tells us about the Jovian system. Across these 14 observations, we find that the region produces no significant X‐ray emission. Key Points: We compare 14 simultaneous Chandra X‐ray Observatory and Hubble Space Telescope UV observations of Jupiter's Northern AuroraeWe detect no statistically significant X‐ray emission from the UV dark polar region (DPR)The DPR expands and the X‐ray and UV emission on the swirl region boundary shifts when the aurora show solar wind compression morphology [ABSTRACT FROM AUTHOR]

Author(s): The Honeybee Genome Sequencing Consortium; Overall project leadership: ; George M. Weinstock [1, 2]; Gene E. Robinson [7, 9, 13, 14]; Principal investigators: ; Richard A. Gibbs [1, 2]; [...]