Convective Steady State in Shallow Cloud Fields.

Shallow cloud fields exhibit different patterns, such as closed or open hexagonal cells and cloud streets. These patterns play a key role in determining the cloud fields' radiative effects, thereby affecting the climate. Here, we show that a large subset of shallow cloud fields forms organized, mesoscale-sized, regular patterns that persist for extended times. It emanates from the steady state of the underlying rigid configuration of convection cells. From a climate perspective, in a sea of cloud complexity, the convective steady-state provides an "island of simplicity." The convective steady state can be parametrized in climate models to better capture the feedback of such cloud fields in a warming climate.

Uncovering the Large-Scale Meteorology That Drives Continental, Shallow, Green Cumulus Through Supervised Classification.

One of the major sources of uncertainty in climate prediction results from the limitations in representing shallow cumulus (Cu) in models. Recently, a class of continental shallow convective Cu was shown to share distinct morphological properties and to emerge globally mostly over forests and vegetated areas, thus named greenCu. Using machine-learning supervised classification, we identify greenCu fields over three regions, from the tropics to mid- and higher-latitudes, and establish a novel satellite-based data set called greenCuDb, consisting of 1° × 1° sized, high-resolution MODIS images. Using greenCuDb in conjunction with ERA5 reanalysis data, we create greenCu composites for different regions and reveal that greenCu are driven by similar large-scale meteorological conditions, regardless of their geographical locations throughout the world's continents. These conditions include distinct profiles of temperature, humidity and large-scale vertical velocity. The boundary layer is anomalously warm and moderately humid, and is accompanied by a strong large-scale subsidence in the free troposphere.

Efficient reduction for diagnosing Hopf bifurcation in delay differential systems: Applications to cloud-rain models.

By means of Galerkin-Koornwinder (GK) approximations, an efficient reduction approach to the Stuart-Landau (SL) normal form and center manifold is presented for a broad class of nonlinear systems of delay differential equations that covers the cases of discrete as well as distributed delays. The focus is on the Hopf bifurcation as a consequence of the critical equilibrium's destabilization resulting from an eigenpair crossing the imaginary axis. The nature of the resulting Hopf bifurcation (super- or subcritical) is then characterized by the inspection of a Lyapunov coefficient easy to determine based on the model's coefficients and delay parameters. We believe that our approach, which does not rely too much on functional analysis considerations but more on analytic calculations, is suitable to concrete situations arising in physics applications. Thus, using this GK approach to the Lyapunov coefficient and the SL normal form, the occurrence of Hopf bifurcations in the cloud-rain delay models of Koren and Feingold (KF) on one hand and Koren, Tziperman, and Feingold on the other are analyzed. Noteworthy is the existence of the KF model of large regions of the parameter space for which subcritical and supercritical Hopf bifurcations coexist. These regions are determined, in particular, by the intensity of the KF model's nonlinear effects. "Islands" of supercritical Hopf bifurcations are shown to exist within a subcritical Hopf bifurcation "sea"; these islands being bordered by double-Hopf bifurcations occurring when the linearized dynamics at the critical equilibrium exhibit two pairs of purely imaginary eigenvalues.

Infection of phytoplankton by aerosolized marine viruses.

Marine viruses constitute a major ecological and evolutionary driving force in the marine ecosystems. However, their dispersal mechanisms remain underexplored. Here we follow the dynamics of Emiliania huxleyi viruses (EhV) that infect the ubiquitous, bloom-forming phytoplankton E. huxleyi and show that EhV are emitted to the atmosphere as primary marine aerosols. Using a laboratory-based setup, we showed that the dynamic of EhV aerial emission is strongly coupled to the host-virus dynamic in the culture media. In addition, we recovered EhV DNA from atmospheric samples collected over an E. huxleyi bloom in the North Atlantic, providing evidence for aerosolization of marine viruses in their natural environment. Decay rate analysis in the laboratory revealed that aerosolized viruses can remain infective under meteorological conditions prevailing during E. huxleyi blooms in the ocean, allowing potential dispersal and infectivity over hundreds of kilometers. Based on the combined laboratory and in situ findings, we propose that atmospheric transport of EhV is an effective transmission mechanism for spreading viral infection over large areas in the ocean. This transmission mechanism may also have an important ecological impact on the large-scale host-virus "arms race" during bloom succession and consequently the turnover of carbon in the ocean.

Exploring the nonlinear cloud and rain equation.

Marine stratocumulus cloud decks are regarded as the reflectors of the climate system, returning back to space a significant part of the income solar radiation, thus cooling the atmosphere. Such clouds can exist in two stable modes, open and closed cells, for a wide range of environmental conditions. This emergent behavior of the system, and its sensitivity to aerosol and environmental properties, is captured by a set of nonlinear equations. Here, using linear stability analysis, we express the transition from steady to a limit-cycle state analytically, showing how it depends on the model parameters. We show that the control of the droplet concentration (N), the environmental carrying-capacity (H0), and the cloud recovery parameter (τ) can be linked by a single nondimensional parameter (µ=N/(ατH0)), suggesting that for deeper clouds the transition from open (oscillating) to closed (stable fixed point) cells will occur for higher droplet concentration (i.e., higher aerosol loading). The analytical calculations of the possible states, and how they are affected by changes in aerosol and the environmental variables, provide an enhanced understanding of the complex interactions of clouds and rain.

The clinical behavior of sinonasal inverted papilloma with cellular dysplasia: case series and review of the literature.

The prognosis and recurrence rate of inverted papilloma (IP) with concomitant cellular dysplasia are not well-delineated. Demographic, clinical and imaging data of all patients who were surgically treated for sinonasal inverted papilloma (SNIP) in our center between 1996 and 2013 were reviewed. Data regarding the coexistence of dysplastic changes or malignancy within the resected tissues were also retrieved. After the exclusion of malignant cases and patients who were lost for follow-up, 92 patients were included in the study. Five patients had coexisting cellular dysplasia (4.7%), four of them had severe dysplasia and one had mild-to-moderate dysplasia. All four cases with severe dysplasia recurred, three were primarily treated endoscopically and one by external approach. Only the case with mild to moderate dysplasia which had been treated by subcranial approach did not recur. Patients with dysplasia had significantly higher recurrence rate than patients without dysplasia (80 vs. 14%, p = 0.019). This significant relation between histology and recurrence remained even after adjustment to tumor extent. The adjusted odd ratio of dysplasia (dysplasia vs. no dysplasia) is 9.7, p = 0.043. SNIP with dysplasia should be treated aggressively and followed closely. The histopathologic investigation of SNIP specimens should always note the presence of dysplasia and its severity. Further investigation on the clinical behavior of SNIP with dysplasia is needed. Multicenter studies are warranted due to the rarity of dysplastic SNIP.

Precipitation-generated oscillations in open cellular cloud fields.

Cloud fields adopt many different patterns that can have a profound effect on the amount of sunlight reflected back to space, with important implications for the Earth's climate. These cloud patterns can be observed in satellite images of the Earth and often exhibit distinct cell-like structures associated with organized convection at scales of tens of kilometres. Recent evidence has shown that atmospheric aerosol particles-through their influence on precipitation formation-help to determine whether cloud fields take on closed (more reflective) or open (less reflective) cellular patterns. The physical mechanisms controlling the formation and evolution of these cells, however, are still poorly understood, limiting our ability to simulate realistically the effects of clouds on global reflectance. Here we use satellite imagery and numerical models to show how precipitating clouds produce an open cellular cloud pattern that oscillates between different, weakly stable states. The oscillations are a result of precipitation causing downward motion and outflow from clouds that were previously positively buoyant. The evaporating precipitation drives air down to the Earth's surface, where it diverges and collides with the outflows of neighbouring precipitating cells. These colliding outflows form surface convergence zones and new cloud formation. In turn, the newly formed clouds produce precipitation and new colliding outflow patterns that are displaced from the previous ones. As successive cycles of this kind unfold, convergence zones alternate with divergence zones and new cloud patterns emerge to replace old ones. The result is an oscillating, self-organized system with a characteristic cell size and precipitation frequency.

Formation of highly porous aerosol particles by atmospheric freeze-drying in ice clouds.

The cycling of atmospheric aerosols through clouds can change their chemical and physical properties and thus modify how aerosols affect cloud microphysics and, subsequently, precipitation and climate. Current knowledge about aerosol processing by clouds is rather limited to chemical reactions within water droplets in warm low-altitude clouds. However, in cold high-altitude cirrus clouds and anvils of high convective clouds in the tropics and midlatitudes, humidified aerosols freeze to form ice, which upon exposure to subsaturation conditions with respect to ice can sublimate, leaving behind residual modified aerosols. This freeze-drying process can occur in various types of clouds. Here we simulate an atmospheric freeze-drying cycle of aerosols in laboratory experiments using proxies for atmospheric aerosols. We find that aerosols that contain organic material that undergo such a process can form highly porous aerosol particles with a larger diameter and a lower density than the initial homogeneous aerosol. We attribute this morphology change to phase separation upon freezing followed by a glass transition of the organic material that can preserve a porous structure after ice sublimation. A porous structure may explain the previously observed enhancement in ice nucleation efficiency of glassy organic particles. We find that highly porous aerosol particles scatter solar light less efficiently than nonporous aerosol particles. Using a combination of satellite and radiosonde data, we show that highly porous aerosol formation can readily occur in highly convective clouds, which are widespread in the tropics and midlatitudes. These observations may have implications for subsequent cloud formation cycles and aerosol albedo near cloud edges.

One stage combined endoscopic and per-oral buccal fat pad approach for large oro-antral-fistula closure with secondary chronic maxillary sinusitis.

There are numerous surgical approaches for oro-antral-fistula (OAF) closure. Secondary sinus disease is still considered by many experts a relative contra indication for primary closure. To describe a single-stage combined endoscopic sinus surgery and per-oral buccal fat pad (BFP) flap approach for large OAF causing chronic maxillary sinusitis. The records of all the patients with OAF and chronic manifestations of secondary rhinosinusitis that were treated between 2010 and 2013 in our tertiary care medical center were reviewed. The exclusion criteria were: OAF ≤ 5 mm, resolved sino-nasal disease, OAF secondary to malignancy, recurrent fistula, medical history that included radiotherapy to the maxillary bone and age <18 years. Each procedure was performed by a team consisting of a rhinologist and a maxillofacial surgeon. The surgical approach included an endoscopic middle antrostomy with maxillary sinus drainage, and a per-oral BFP regional flap for OAF closure. Total OAF closure, complications and need for revision surgeries. Forty-five patients that underwent OAF closure together with sinus surgery using a combined endoscopic sinus surgery (ESS) and BFP flap approach met the inclusion criteria. There were 28 males and 17 females with a mean ± SD age of 53.5 ± 14.9 years (range 22-80 years). The presenting signs and symptoms included purulent rhinorrhea (n = 22, 48.9 %), foreign body in sinus (n = 10, 22.2 %) nasal congestion (n = 7, 15.5 %), halitosis (n = 6, 13.3 %) and pain (n = 5, 12.2 %). Surgical complications included local pain (n = 2, 4.4 %), persistent rhinitis (n = 2, 4.4 %) and synechia (n = 1, 2.2 %). One patient required revision surgery due to an unresolved OAF. The OAF of all the other 44 patients (97.8 %) was closed after the first procedure and the paranasal sinuses on the treated side were completely recovered. The mean follow-up time for the group was 7.6 ± 4.3 months (7-21 months), and no untoward sequelae or recurrence were reported. Combined, one step, endoscopic Maxillary sinus drainage together with per-oral BFP flap approach is an efficacious surgical approach for safe closure of OAFs that are complicated with secondary chronic maxillary sinusitis.

Combined maxillary sinus floor elevation and endonasal endoscopic sinus surgery for coexisting inflammatory sinonasal pathologies: a one-stage double-team procedure.

OBJECTIVES: To report our experience with combined one-stage double-team maxillary sinus floor elevation (SFE) and endonasal endoscopic sinus surgery (ESS) procedure for concomitant inflammatory sinonasal pathologies. MATERIAL AND METHODS: Clinical records of all patients that underwent maxillary SFE in conjunction with endonasal ESS for the treatment of inflammatory sinonasal pathologies between 2011 and 2013 were retrospectively reviewed. All included patients had a sinonasal-related pathology that was first suggested by the referring physician and was later confirmed clinically and radiographically by our combined team comprised of otorhinolaryngologist and maxillofacial surgeons. RESULTS: Fifteen combined SFE+ESS surgeries were performed using either xenograft-allograft mixture or autograft-xenograft-allograft mixture. The study group included seven males and eight females, whose median age was 55 years (range, 45-78 years). Seven patients underwent a unilateral SFE, and eight patients underwent bilateral SFEs. During the same session, four patients also underwent septoplasty for deviated nasal septum, five patients underwent bilateral maxillary antrostomy, 10 patients underwent unilateral maxillary antrostomy, and six patients underwent maxillary sinus cyst resection. Seven combined procedures were performed under active infection. There were no intra-operative complications, and all SFE+ESS combined procedures were successful. Three patients required extended postoperative antibiotic treatment for persistent sinusitis. One patient reported infraorbital hypoesthesia. CONCLUSIONS: We first report the promising outcomes of the double-team one-stage SFE+ESS procedure performed by a combined team of otorhinolaryngologist and maxillofacial surgeons, including on patients presenting with an infection of the sinuses at the time of surgery.

Aerosol-cloud-precipitation system as a predator-prey problem.

We show that the aerosol-cloud-precipitation system exhibits characteristics of the predator-prey problem in the field of population dynamics. Both a detailed large eddy simulation of the dynamics and microphysics of a precipitating shallow boundary layer cloud system and a simpler model built upon basic physical principles, reproduce predator-prey behavior with rain acting as the predator and cloud as the prey. The aerosol is shown to modulate the predator-prey response. Steady-state solution to the proposed model shows the known existence of bistability in cloudiness. Three regimes are identified in the time-dependent solutions: (i) the weakly precipitating regime where cloud and rain coexist in a quasi steady state; (ii) the moderately drizzling regime where limit-cycle behavior in the cloud and rain fields is produced; and (iii) the heavily precipitating clouds where collapse of the boundary layer is predicted. The manifestation of predator-prey behavior in the aerosol-cloud-precipitation system is a further example of the self-organizing properties of the system and suggests that exploiting principles of population dynamics may help reduce complex aerosol-cloud-rain interactions to a more tractable problem.

Impact of airborne algicidal bacteria on marine phytoplankton blooms.

Ocean microbes are involved in global processes such as nutrient and carbon cycling. Recent studies indicated diverse modes of algal-bacterial interactions, including mutualism and pathogenicity, which have a substantial impact on ecology and oceanic carbon sequestration, and hence, on climate. However, the airborne dispersal and pathogenicity of bacteria in the marine ecosystem remained elusive. Here, we isolated an airborne algicidal bacterium, Roseovarius nubinhibens, emitted to the atmosphere as primary marine aerosol (referred also as sea spray aerosols) and collected above a coccolithophore bloom in the North Atlantic Ocean. The aerosolized bacteria retained infective properties and induced lysis of Gephyrocapsa huxleyi cultures.This suggests that the transport of marine bacteria through the atmosphere can effectively spread infection agents over vast oceanic regions, highlighting its significance in regulating the cell fate in algal blooms.

Observational evidence of changing cloud macro-physical properties under warming climate over the Indian summer monsoon region.

The cloud responses to global warming are captured in various global climate models with distinct inferences on changes in cloud vertical structure as function of surface warming. However, long term observational evidences are scarce to validate the model outputs. Here, we have studied the changes in radiosonde derived cloud macro-physical properties and their association with other atmospheric variables during the period 2000-2019 in response to warming climate over the Indian summer monsoon region. We have observed a statistically significant increase in the frequency of cloudy days (∼13 % decade-1), high-level clouds (HLCs ∼11 % decade-1) and simultaneous decrease in low-level clouds (LLCs ∼8 % decade-1) over the Indian region during the monsoon season. The multiple linear regression, principle component analyses and further correlation analyses suggest significant associations between cloud vertical structure variations and large-scale climate indicators, such as global warming and El Niño-Southern Oscillation. The vertical extension of the tropospheric column and the upward shift of clouds, attributed to global warming, explain the changes observed in both HLCs and LLCs. These results contribute to a deeper understanding of the dynamic interplay between global climate change and regional cloud dynamics, with implications for weather and climate modeling.

The Associations between the Maxillary Sinus Volume, Infraorbital Ethmoid Cells, and the Infraorbital Canal: A CT-Based Study.

This CT-based study aimed to characterize and explain the existence of two anatomical structures positioned near the maxillary sinuses, which are of clinical relevance in rhinology and maxillofacial surgery. A total of 182 head scans (92 males and 90 females) were inspected for infraorbital ethmoid cells (IECs) and for the type (route) of infraorbital canal (IOC). The maxillary sinuses were segmented, and their volumes were measured. Statistical analysis was conducted to reveal the associations between the two anatomical variations, namely, sex and the maxillary sinus volume. Infraorbital ethmoid cells were noted in 43.9% of the individuals studied; they were more frequent in males (53.3%) than in females (34.4%). The descending infraorbital nerve (type 3 IOC) was found in 13.2% of individuals and was independent of sex. Infraorbital ethmoid cells were associated with the IOC types. The maxillary sinus volume was found to be sex-dependent. A large sinus volume is significantly associated with IOC Type 3 (the descending canal) and the presence of IEC. Dentists, radiologists, and surgeons should be aware that individuals with extensive pneumatization of the maxillary sinuses are more likely to display a descending IOC and IEC. These findings should be studied, along with CT scans, before treatment and surgery.

Open science resources from the Tara Pacific expedition across coral reef and surface ocean ecosystems.

The Tara Pacific expedition (2016-2018) sampled coral ecosystems around 32 islands in the Pacific Ocean and the ocean surface waters at 249 locations, resulting in the collection of nearly 58 000 samples. The expedition was designed to systematically study warm-water coral reefs and included the collection of corals, fish, plankton, and seawater samples for advanced biogeochemical, molecular, and imaging analysis. Here we provide a complete description of the sampling methodology, and we explain how to explore and access the different datasets generated by the expedition. Environmental context data were obtained from taxonomic registries, gazetteers, almanacs, climatologies, operational biogeochemical models, and satellite observations. The quality of the different environmental measures has been validated not only by various quality control steps, but also through a global analysis allowing the comparison with known environmental large-scale structures. Such publicly released datasets open the perspective to address a wide range of scientific questions.

Generic generation of noise-driven chaos in stochastic time delay systems: Bridging the gap with high-end simulations.

Nonlinear time delay systems produce inherently delay-induced periodic oscillations, which are, however, too idealistic compared to observations. We exhibit a unified stochastic framework to systematically rectify such oscillations into oscillatory patterns with enriched temporal variabilities through generic, nonlinear responses to stochastic perturbations. Two paradigms of noise-driven chaos in high dimension are identified, fundamentally different from chaos triggered by parameter-space noise. Noteworthy is a low-dimensional stretch-and-fold mechanism, leading to stochastic strange attractors exhibiting horseshoe-like structures mirroring turbulent transport of passive tracers. The other is high-dimensional , with noise acting along the critical eigendirection and transmitted to "deeper" stable modes through nonlinearity, leading to stochastic attractors exhibiting swarm-like behaviors with power-law and scale break properties. The theory is applied to cloud delay models to parameterize missing physics such as intermittent rain and Lagrangian turbulent effects. The stochastically rectified model reproduces with fidelity complex temporal variabilities of open-cell oscillations exhibited by high-end cloud simulations.

Safety of Endoscopic Sinus Surgery in the Elderly-Are Octogenarian Patients at a Higher Risk?

BACKGROUND: Surgeons are often faced with concerns regarding the risks versus benefits of endoscopic sinus surgery (ESS) in elderly patients. OBJECTIVE: To analyze the risk for complications of ESS in the elderly (age ≥70 years) compared to younger patients, with emphasis on octogenarians. METHODS: Retrospective review of medical charts of adult patients who underwent ESS at a tertiary referral center during the years 2014 to 2018. RESULTS: We compared 128 elderly patients with 276 matched younger patients. In the elderly group mean age was 76 years (range, 70-91 years ). Thirty-one elderly patients were 80 years or older. Surgical complications in the elderly patients were 3.9%. Minor complications were 2.3% and major complications were 1.7%. The surgical complications rate was similar in the younger group (8%, P value: .127). Medical complications were observed in 2.3% comparing to 0.7% in younger patients. Interestingly, age, revision surgery, extent and duration of surgery, and modality of anesthesia were not identified as risk factors. Only ischemic heart disease (IHD) was identified as a risk factor for complications in a multivariate analysis in elderly patients. Comparison of elderly patients younger than 80 years with octogenarians revealed no difference in complication rate between these groups. CONCLUSIONS: Overall, ESS was found to be a safe procedure in elderly patients compared to younger patients. Octogenarian patients should not be denied upfront surgery. IHD is a risk factor for complications in elderly patients.

Record-breaking aerosol levels explained by smoke injection into the stratosphere.

The early months of 2020 showed record-breaking levels of aerosol optical depth (AOD) over the Southern Hemisphere (SH). Apart from the tropics, monthly AOD values over most of the SH exceeded the average by more than three standard deviations. This anomalous AOD is attributed to a combination of the intensity and location of the Australian bushfires. The fires took place south enough, where the tropopause altitude is relatively low, within the mid-latitude cyclone belt. This location allowed for deep convection over and downwind of the fires, which transported the smoke to the stratosphere, where its lifetime is an order of magnitude longer than it would have been in the lower atmosphere. The lower bound of the stratospheric smoke mass in January 2020 was ~2.1 ± 1 teragrams, which lead to cooling by more than 1.0 ± 0.6 watts per square meter over cloud-free oceanic areas.

Surgical Site Reassessment: An Important Step in Improving Clinical Outcomes Following Pediatric Endoscopic Dacryocystorhinostomy.

PURPOSE: To report the authors' experience with endoscopic unpowered dacryocystorhinostomy in the treatment of pediatric nasolacrimal duct obstruction, and to evaluate whether surgical site reassessment (after the appropriate healing period) affects clinical outcomes. METHODS: This retrospective study included 47 children aged between 1.5 and 17.0 years (mean age: 6.9 years) who underwent endoscopic unpowered dacryocystorhinostomy between 2014 and 2019 at one tertiary care hospital. Twenty-six patients required unilateral and 21 required bilateral endoscopic dacryocystorhinostomy. The main outcome measures were duct patency on lacrimal irrigation ("anatomical success") and resolution of symptoms ("clinical success") over 6 months of postoperative follow-up. RESULTS: Sixty-eight dacryocystorhinostomy procedures were performed. Surgical site reassessment during tube removal was performed in 52 of 68 cases. Five cases (9.6%) required treatment of local pathologies, only after which was symptomatic relief achieved. Overall anatomical success was observed in 49 (94.2%) of the 52 cases in which nasal endoscopy was performed, including the 5 cases treated during reevaluation. Clinical success was observed in 63 (92.6%) cases. CONCLUSIONS: Pediatric endoscopic dacryocystorhinostomy is an effective surgical procedure used to correct nasolacrimal system obstruction resistant to conservative measures. The unpowered endoscopic dacryocystorhinostomy technique is practical and safe in the pediatric population. Surgical site reassessment allows treating local pathologies threatening ostium patency and increases clinical success rates. [J Pediatr Ophthalmol Strabismus. 2021;58(3):168-173.].

Endoscopic treatment of ectopic teeth in the maxillary sinus.

BACKGROUND: Ectopic teeth in maxillary sinus is rare and are usually removed via sub-labial trans-canine fossa approach (SLCFA). The aim of our study was to present our experience with extraction of ectopic teeth in the maxillary sinus via transnasal endoscopic approach (TEA). MATERIAL AND METHODS: Rhinologists were asked to share their experience in the management of ectopic teeth in the maxillary sinus. Data were reviewed retrospectively. RESULTS: Eleven cases were reported in 10 patients from 2010 to 2019, six males and four females with a mean age of 33.5 +/-17 years (range 16 to 61). Seven patients complained of sinonasal symptoms, two were diagnosed incidentally during routine dental work-up, and one had oro-antral fistula. In eight patients, a cyst coexisted within the maxillary sinus. Teeth were located arbitrarily within the sinus. All cases were operated by TEA. One patient had self-limited periorbital emphysema, one had transient cheek numbness, and one had early post-operative bleeding that stopped after endoscopic cauterization. Long-term follow-up revealed good clinical outcomes. CONCLUSIONS: Transnasal endoscopic removal of ectopic teeth from the maxillary sinus is a feasible and rational approach when SLCFA is contraindicated. Key words:Ectopic teeth, dentigerous cyst, endoscopic sinus surgery, Caldwell-Luc.