A review of the melliferous flora of Yucatan peninsula, Mexico, on the basis for the honey production cycle.

BACKGROUND: The Yucatan Peninsula (YP) is one of the most important regions in global apiculture. Hence, this work reviews and integrates the knowledge of the species diversity, growth habits, ecosystems, floral calendars during the apiculture production cycles and the types of vegetation represented in the melliferous flora (MF) of the YP; as a basis for proposing selection strategies locating suitable apiculture production areas for local beekeepers and help in the economic development of the region. METHODS: A comprehensive review of the MF literature was carried out using the snowball method to determine and update the number of species useful for apiculture. The growth habits and flower calendars were determined through a review of the literature and databases of specimens from the herbaria CICY, UCAM and MEXU. RESULTS: The YP reports a total of 935 taxa of MF (98 families and 498 genera); of these, Campeche has 812 taxa, followed by Quintana Roo (786) and Yucatán (767). The MF is made up of herbs (282), followed by shrubs (260), trees (229), climbers (82), woody climbers (67) palms (14) and parasitic plant (1). CONCLUSION: Of the 935 species of MF registered at the regional level, a high number of species have flowering throughout the year, however, not all of these species are considered useful for local commercial apiculture. Only a select group of 23 species are considered of major importance for local apiculture industry.

Coherent spore dispersion via drop-leaf interaction.

The dispersion of plant pathogens, such as rust spores, is responsible for more than 20% of global crop yield loss annually. However, the release mechanism of pathogens from flexible plant surfaces into the canopy is not well understood. In this study, we investigated the interplay between leaf elasticity and rainfall, revealing how a flexible leaf structure can generate a lateral flow stream, with embedded coherent structures that enhance transport. We first modeled the linear coupling between drop momentum, leaf vibration, and the stream flux from leaf surfaces. With Lagrangian diagnostics, we further mapped out the nested coherent structures around the fluttering profile, providing a dynamical description for local spore delivery. We hope the mechanistic details extracted here can facilitate the construction of physically informed analytical models for local crop disease management.

Morphology of pig nasal structure and modulation of airflow and basic thermal conditioning.

Mammals have presumably evolved to adapt to a diverse range of ambient environmental conditions through the optimized heat and mass exchange. One of the crucial biological structures for survivability is the nose, which efficiently transports and thermally preconditions the external air before reaching the internal body. Nasal mucosa and cavity help warm and humidify the inhaled air quickly. Despite its crucial role, the morphological features of mammal noses and their effect in modulating the momentum of the inhaled air, heat transfer dynamics, and particulate trapping remain poorly understood. Tortuosity of the nasal cavity in high-olfactory mammalian species, such as pigs and opossum, facilitates the formation of complex airflow patterns inside the nasal cavity, which leads to the screening of particulates from the inhaled air. We explored basic nasal features in anatomically realistic nasal pathways, including tortuosity, radius of curvature, and gap thickness; they show strong power-law correlations with body weight. Complementary inspection of tortuosity with idealized conduits reveals that this quantity is central in particle capture efficiency. Mechanistic insights into such nuances can serve as a tipping point to transforming nature-based designs into practical applications. In-depth characterization of the fluid-particle interactions in nasal cavities is necessary to uncover nose mechanistic functionalities. It is instrumental in developing new devices and filters in a number of engineering processes.

No magic bullet: Limiting in-school transmission in the face of variable SARS-CoV-2 viral loads.

In the face of a long-running pandemic, understanding the drivers of ongoing SARS-CoV-2 transmission is crucial for the rational management of COVID-19 disease burden. Keeping schools open has emerged as a vital societal imperative during the pandemic, but in-school transmission of SARS-CoV-2 can contribute to further prolonging the pandemic. In this context, the role of schools in driving SARS-CoV-2 transmission acquires critical importance. Here we model in-school transmission from first principles to investigate the effectiveness of layered mitigation strategies on limiting in-school spread. We examined the effect of masks and air quality (ventilation, filtration and ionizers) on steady-state viral load in classrooms, as well as on the number of particles inhaled by an uninfected person. The effectiveness of these measures in limiting viral transmission was assessed for variants with different levels of mean viral load (ancestral, Delta, Omicron). Our results suggest that a layered mitigation strategy can be used effectively to limit in-school transmission, with certain limitations. First, poorly designed strategies (insufficient ventilation, no masks, staying open under high levels of community transmission) will permit in-school spread even if some level of mitigation is present. Second, for viral variants that are sufficiently contagious, it may be difficult to construct any set of interventions capable of blocking transmission once an infected individual is present, underscoring the importance of other measures. Our findings provide practical recommendations; in particular, the use of a layered mitigation strategy that is designed to limit transmission, with other measures such as frequent surveillance testing and smaller class sizes (such as by offering remote schooling options to those who prefer it) as needed.

On the design of particle filters inspired by animal noses.

Passive filtering is a common strategy to reduce airborne disease transmission and particulate contaminants across scales spanning orders of magnitude. The engineering of high-performance filters with relatively low flow resistance but high virus- or particle-blocking efficiency is a non-trivial problem of paramount relevance, as evidenced in the variety of industrial filtration systems and face masks. Next-generation industrial filters and masks should retain sufficiently small droplets and aerosols while having low resistance. We introduce a novel 3D-printable particle filter inspired by animals' complex nasal anatomy. Unlike standard random-media-based filters, the proposed concept relies on equally spaced channels with tortuous airflow paths. These two strategies induce distinct effects: a reduced resistance and a high likelihood of particle trapping by altering their trajectories with tortuous paths and induced local flow instability. The structures are tested for pressure drop and particle filtering efficiency over different airflow rates. We have also cross-validated the observed efficiency through numerical simulations. We found that the designed filters exhibit a lower pressure drop, compared to commercial masks and filters, while capturing particles bigger than approximately 10 µm. Our findings could facilitate a novel and scalable filter concept inspired by animal noses.

Computational characterization of inhaled droplet transport to the nasopharynx.

How human respiratory physiology and the transport phenomena associated with inhaled airflow in the upper airway proceed to impact transmission of SARS-CoV-2, leading to the initial infection, stays an open question. An answer can help determine the susceptibility of an individual on exposure to a COVID-2019 carrier and can also provide a preliminary projection of the still-unknown infectious dose for the disease. Computational fluid mechanics enabled tracking of respiratory transport in medical imaging-based anatomic domains shows that the regional deposition of virus-laden inhaled droplets at the initial nasopharyngeal infection site peaks for the droplet size range of approximately 2.5-19 [Formula: see text]. Through integrating the numerical findings on inhaled transmission with sputum assessment data from hospitalized COVID-19 patients and earlier measurements of ejecta size distribution generated during regular speech, this study further reveals that the number of virions that may go on to establish the SARS-CoV-2 infection in a subject could merely be in the order of hundreds.

Numerical evaluation of spray position for improved nasal drug delivery.

Topical intra-nasal sprays are amongst the most commonly prescribed therapeutic options for sinonasal diseases in humans. However, inconsistency and ambiguity in instructions show a lack of definitive knowledge on best spray use techniques. In this study, we have identified a new usage strategy for nasal sprays available over-the-counter, that registers an average 8-fold improvement in topical delivery of drugs at diseased sites, when compared to prevalent spray techniques. The protocol involves re-orienting the spray axis to harness inertial motion of particulates and has been developed using computational fluid dynamics simulations of respiratory airflow and droplet transport in medical imaging-based digital models. Simulated dose in representative models is validated through in vitro spray measurements in 3D-printed anatomic replicas using the gamma scintigraphy technique. This work breaks new ground in proposing an alternative user-friendly strategy that can significantly enhance topical delivery inside human nose. While these findings can eventually translate into personalized spray usage instructions and hence merit a change in nasal standard-of-care, this study also demonstrates how relatively simple engineering analysis tools can revolutionize everyday healthcare. Finally, with respiratory mucosa as the initial coronavirus infection site, our findings are relevant to intra-nasal vaccines that are in-development, to mitigate the COVID-19 pandemic.

Nasal Airflow Changes With Bioabsorbable Implant, Butterfly, and Spreader Grafts.

OBJECTIVES/HYPOTHESIS: Internal nasal valve compromise is a major cause of nasal obstruction, with a growing number of ways to treat this condition. In this study, we compared the effects of butterfly graft, spreader graft, and the bioabsorbable nasal implant on nasal airflow resistance. STUDY DESIGN: Cadaver study. METHODS: Computational fluid dynamics (CFD) simulations were completed from nine preoperative and postoperative cadaveric subjects. Each cadaveric head underwent placement of a bioabsorbable nasal implant (BNI) (Spirox Latera; Stryker ENT, Plymouth, MN), butterfly graft, or spreader graft. Pre- and postoperative computed tomography (CT) scans were used to generate three-dimensional models of the nasal airway used in steady-state CFD simulations of airflow and heat transfer during inspiration. RESULTS: Butterfly graft placement resulted in a mean improvement in nasal airway resistance of 24.9% (±7.3), whereas BNI placement resulted in a 6.7% (±1.2) improvement, and spreader graft placement also resulted in a consistent improvement of 2.6% (±13.5). Pressure within the main nasal cavity was consistently lower following butterfly graft placement versus a spreader graft or BNI. Butterfly and spreader graft placement also resulted in modest improvements in airflow allocation, whereas BNI demonstrated more variation (-1% to 12%). Heat flux was not significantly different; however, a small improvement in total heat flux was seen with all three interventions. CONCLUSIONS: The results of this study demonstrate reduction in nasal airway resistance in all three surgical interventions, with the butterfly graft demonstrating superiority to the other two techniques. However, these data only reflect a static environment and not dynamic changes in airflow seen during respiration. LEVEL OF EVIDENCE: NA Laryngoscope, 130:E817-E823, 2020.

Intranasal Corticosteroids: Patient Administration Angles and Impact of Education.

INTRODUCTION: Intranasal corticosteroids sprays (INCS) are first line treatment for allergic rhinitis and are frequently used for chronic rhinosinusitis. Improperly aiming INCS increases the risk of epistaxis and may decrease the efficacy of the medication. The goal of this study was to determine how patients position INCS for drug delivery and if verbal or written instructions improve their positioning. METHODS: Patients in rhinology clinics were photographed while administering a generic spray bottle. The angle of the spray bottle relative to the patients' head and a fixed background was determined. RESULTS: A total of 46 participants were included. The average spray angle for the right naris was 10.1° towards the septum and 67.2° below the Frankfurt Horizontal plane. The average spray angle for the left naris was 4.5° towards the septum and 62.2° below the Frankfurt horizontal plane. The angle of the spray bottle ranged from 50° toward the septum to 43° away from the septum. Only 8 patients aimed away from the septum for both nares. Patients who recalled receiving verbal and written instructions aimed the INCS bottle at the lateral wall and inferior turbinate in contrast to patients who only received one form of instruction or no instructions. CONCLUSIONS: Most patients (83%) incorrectly aim INCS when compared to current guidelines. There was statistically significant improvement in the positioning of patients who reported receiving both verbal and written instruction; however, this study highlights a greater need for patient education.

Perceptions of the local beekeepers on the diversity and flowering phenology of the melliferous flora in the community of Xmabén, Hopelchén, Campeche, Mexico.

BACKGROUND: The knowledge of native melliferous flora (MF) may contribute to identify the diversity of species available for beekeeping activities during the dry and rainy seasons of the year in the Yucatan Peninsula (YP) region. The acute shortage of food resources considerably reduce local honey production and needs to be addressed appropriately. The objective of this study has been identifying the local MF, their nectar and pollen contribution, their flowering patterns, and the criteria of the vegetation to be established adjacent to local apiaries for stable production of quality honey. The study also investigates how this approach helps to complete the annual flowering cycle required to maintain the honeybee colonies, thereby preventing swarm escapes during periods of acute food stress in the community of Xmabén, Hopelchén, Campeche, Mexico. METHODOLOGY: We conducted a comprehensive survey based on interviews with 40 local beekeepers and a review of herbarium specimens (CICY) of the database of the global information network on the native MF biodiversity with high apiculture potential, the contribution of nectar and pollen they provide, and their flowering patterns. Furthermore, we documented interviews with the same beekeepers on the necessary conditions for establishing the ideal components of vegetation in areas adjacent to apiaries for high-quality honey production in the Xmabén community of Hopelchén, Campeche, Mexico. RESULTS: We have identified 56 native MF species with apiculture potential, that need to be planted around the apiaries for assisting honeybees in successfully running the beekeeping production cycle. Hence, the MF diversity of Xmabén community constitutes a valuable resource for successful beekeeping in the region and adjoining localities. We found that 22.5% of local beekeepers are dedicated exclusively to apilcilture, while 77.5% practice it as a secondary activity due to better sources of income in agriculture (60%), masonry (10%), and livestock management (7.5%). The data generated can help in further expansion of the local apiaries, beekeeping business, and in building future opportunities for the local apiculture industry. Indigenous knowledge of the beekeepers was comprehensive and corroborated the technical information on MF collected from the herbarium, further emphasizing the value of indigenous knowledge on traditional beekeeping practices. CONCLUSION: From the perspective of human ecology, our study reveals the need of collecting, analyzing, and interpreting indigenous knowledge to facilitate traditional beekeeping practices of the region without using expensive, modern technology to solve ecosystem-based problems through long-term, sustainable, traditional, and environment friendly approaches.

Comparative study of simulated nebulized and spray particle deposition in chronic rhinosinusitis patients.

BACKGROUND: Topical intranasal drugs are widely prescribed for chronic rhinosinusitis (CRS), although delivery can vary with device type and droplet size. The study objective was to compare nebulized and sprayed droplet deposition in the paranasal sinuses and ostiomeatal complex (OMC) across multiple droplet sizes in CRS patients using computational fluid dynamics (CFD). METHODS: Three-dimensional models of sinonasal cavities were constructed from computed tomography (CT) scans of 3 subjects with CRS refractory to medical therapy using imaging software. Assuming steady-state inspiratory airflow at resting rate, CFD was used to simulate 1-µm to 120-µm sprayed droplet deposition in the left and right sinuses and OMC with spray nozzle positioning as in current nasal spray use instructions. Zero-velocity nebulization simulations were performed for 1-µm to 30-µm droplet sizes, maximal sinus and OMC deposition fractions (MSDF) were obtained, and sizes that achieved at least 50% of MSDF were identified. Nebulized MSDF was compared to sprayed droplet deposition. We also validated CFD framework through in vitro experiments. RESULTS: Among nebulized droplet sizes, 11-µm to 14-µm droplets achieved at least 50% of MSDF in all 6 sinonasal cavities. Four of 6 sinonasal cavities had greater sinus and OMC deposition with nebulized droplets than with sprayed droplets at optimal sizes. CONCLUSION: Nebulized droplets may target the sinuses and OMC more effectively than sprayed particles at sizes achieving best deposition. Further studies are needed to confirm our preliminary findings. Several commercial nasal nebulizers have average particle sizes outside the optimal nebulized droplet size range found here, suggesting potential for product enhancement.

Impact of endoscopic craniofacial resection on simulated nasal airflow and heat transport.

BACKGROUND: Endoscopic craniofacial resections (CFR) are performed for extensive anterior skull base lesions. This surgery involves removal of multiple intranasal structures, potentially leading to empty nose syndrome (ENS). However, many patients remain asymptomatic postoperatively. Our objective was to analyze the impact of CFR on nasal physiology and airflow using computational fluid dynamics (CFD). This is the first CFD analysis of post-CFR patients. METHODS: Three-dimensional sinonasal models were constructed from 3 postoperative images using MimicsTM . Hybrid computational meshes were created. Steady inspiratory airflow and heat transport were simulated at patient-specific flow rates using shear stress transport k-omega turbulent flow modeling in FluentTM . Simulated average heat flux (HF) and surface area where HF exceeded 50 W/m2 (SAHF50) were compared with laminar simulations in 9 radiographically normal adults. RESULTS: Three adults underwent CFR without developing ENS. Average HF (W/m2 ) were 132.70, 134.84, and 142.60 in the CFR group, ranging from 156.24 to 234.95 in the nonoperative cohort. SAHF50 (m2 ) values were 0.0087, 0.0120, and 0.0110 in the CFR group, ranging from 0.0082 to 0.0114 in the radiographically normal cohort. SAHF50 was distributed throughout the CFR cavities, with increased HF at the roof and walls compared with the nonoperative cohort. CONCLUSION: Average HF was low in the CFR group compared with the nonoperative group. However, absence of ENS in most CFR patients may be due to large stimulated mucosal surface area, commensurate with the nonoperative cohort. Diffuse distribution of stimulated area may result from turbulent mixing after CFR. To better understand heat transport post-CFR, a larger cohort is necessary.

Upper airway reconstruction using long-range optical coherence tomography: Effects of airway curvature on airflow resistance.

OBJECTIVES: Adenotonsillectomy (AT) is commonly used to treat upper airway obstruction in children, but selection of patients who will benefit most from AT is challenging. The need for diagnostic evaluation tools without sedation, radiation, or high costs has motivated the development of long-range optical coherence tomography (LR-OCT), providing real-time cross-sectional airway imaging during endoscopy. Since the endoscope channel location is not tracked in conventional LR-OCT, airway curvature must be estimated and may affect predicted airway resistance. The study objective was to assess effects of three realistic airway curvatures on predicted airway resistance using computational fluid dynamics (CFD) in LR-OCT reconstructions of the upper airways of pediatric patients, before and after AT. METHODS: Eight subjects (five males, three females, aged 4-9 years) were imaged using LR-OCT before and after AT during sedated endoscopy. Three-dimensional (3D) airway reconstructions included three airway curvatures. Steady-state, inspiratory airflow simulations were conducted under laminar conditions, along with turbulent simulations for one subject using the k-ω turbulence model. Airway resistance (pressure drop/flow) was compared using two-tailed Wilcoxon signed rank tests. RESULTS: Regardless of the airway curvatures, CFD findings corroborate a surgical end-goal with computed post-operative airway resistance significantly less than pre-operative (P < 0.01). The individual resistances did not vary significantly for different airway curvatures (P > 0.25). Resistances computed using turbulent simulations differed from laminar results by less than ∼5%. CONCLUSIONS: The results suggest that reconstruction of the upper airways from LR-OCT imaging data may not need to account for airway curvature to be predictive of surgical effects on airway resistance. Lasers Surg. Med. 51:150-160, 2019. © 2018 Wiley Periodicals, Inc.

Comparison of Airflow Between Spreader Grafts and Butterfly Grafts Using Computational Flow Dynamics in a Cadaveric Model.

IMPORTANCE: Nasal valve compromise is a major cause of nasal obstruction, and multiple methods have been developed to address it. OBJECTIVE: To compare nasal airflow resistance, airflow partitioning, and mucosal cooling (heat flux) before and after 2 surgical interventions, butterfly and spreader graft placement, used to treat nasal valve compromise. DESIGN, SETTING, AND PARTICIPANTS: In this cadaveric tissue study, 4 fresh cadaveric heads underwent both spreader graft and butterfly graft surgical procedures in alternating sequence in March 2016. Preoperative and postoperative computed tomographic scans were used to generate 3-dimensional (3-D) models of the nasal airway. These models were then used in steady state computational fluid dynamics simulations of airflow and heat transfer during inspiration. INTERVENTION: Butterfly and spreader graft techniques. MAIN OUTCOMES AND MEASURES: Nasal airflow resistance, airflow partitioning, and heat flux. RESULTS: Donors 1, 2, and 3 were white males; donor 4, a white female. Computational fluid dynamics simulations during inspiration in 3-D models generated from preoperative and postoperative computed tomographic scans of the 4 cadaveric heads indicated reductions from preoperative values in nasal airflow resistance associated with both butterfly grafts (range, 20%-51%) and spreader grafts (range, 2%-29%). Butterfly grafts were associated with a greater reduction in nasal airflow resistance in models of all 4 cadaveric heads. Changes from preoperative values for heat flux, a biophysical variable that correlates with the subjective sensation of nasal patency, were more variable, ranging from -11% to 4% following butterfly grafts and -9% to 10% following spreader grafts. The preoperative airflow allocation in the left and right nostrils improved consistently with the butterfly graft. With the spreader graft, there were improvements for donors 1 and 4, but the allocations were worse for donors 2 and 3. CONCLUSIONS AND RELEVANCE: The results of this study suggest that the more recently developed butterfly graft technique may be associated with a similar level of improved nasal airflow as that observed with the use of a spreader graft in nasal valve compromise. Both interventions were associated with comparable changes in heat flux. Because this study addressed only static internal nasal valve stenosis, even greater differences in air flow and heat flux between the 2 techniques may be anticipated in a dynamic model. Further investigation in patients is warranted. LEVEL OF EVIDENCE: NA.

Ideal Particle Sizes for Inhaled Steroids Targeting Vocal Granulomas: Preliminary Study Using Computational Fluid Dynamics.

Objectives Vocal fold granulomas are benign lesions of the larynx commonly caused by gastroesophageal reflux, intubation, and phonotrauma. Current medical therapy includes inhaled corticosteroids to target inflammation that leads to granuloma formation. Particle sizes of commonly prescribed inhalers range over 1 to 4 µm. The study objective was to use computational fluid dynamics to investigate deposition patterns over a range of particle sizes of inhaled corticosteroids targeting the larynx and vocal fold granulomas. Study Design Retrospective, case-specific computational study. Setting Tertiary academic center. Subjects/Methods A 3-dimensional anatomically realistic computational model of a normal adult airway from mouth to trachea was constructed from 3 computed tomography scans. Virtual granulomas of varying sizes and positions along the vocal fold were incorporated into the base model. Assuming steady-state, inspiratory, turbulent airflow at 30 L/min, computational fluid dynamics was used to simulate respiratory transport and deposition of inhaled corticosteroid particles ranging over 1 to 20 µm. Results Laryngeal deposition in the base model peaked for particle sizes 8 to 10 µm (2.8%-3.5%). Ideal sizes ranged over 6 to 10, 7 to 13, and 7 to 14 µm for small, medium, and large granuloma sizes, respectively. Glottic deposition was maximal at 10.8% for 9-µm-sized particles for the large posterior granuloma, 3 times the normal model (3.5%). Conclusion As the virtual granuloma size increased and the location became more posterior, glottic deposition and ideal particle size generally increased. This preliminary study suggests that inhalers with larger particle sizes, such as fluticasone propionate dry-powder inhaler, may improve laryngeal drug deposition. Most commercially available inhalers have smaller particles than suggested here.

On computational fluid dynamics models for sinonasal drug transport: Relevance of nozzle subtraction and nasal vestibular dilation.

Generating anatomically realistic 3-dimensional (3D) models of the human sinonasal cavity for numerical investigations of sprayed drug transport presents a host of methodological ambiguities. For example, subject-specific radiographic images used for 3D reconstructions typically exclude spray bottles. Subtracting a bottle contour from the 3D airspace and dilating the anterior nasal vestibule for nozzle placement augment the complexity of model building. So we explored the question: how essential are these steps to adequately simulate nasal airflow and identify the optimal delivery conditions for intranasal sprays? In particular, we focused on particle deposition patterns in the maxillary sinus, a critical target site for chronic rhinosinusitis. The models were reconstructed from postsurgery computed tomography scans for a 39-year-old Caucasian male, with chronic rhinosinusitis history. Inspiratory airflow patterns during resting breathing are reliably tracked through computational fluid dynamics-based steady-state laminar-viscous modeling, and such regimes portray relative lack of sensitivity to inlet perturbations. Consequently, we hypothesized that the posterior airflow transport and the particle deposition trends should not be radically affected by the nozzle subtraction and vestibular dilation. The study involved 1 base model and 2 derived models; the latter 2 with nozzle contours (2 different orientations) subtracted from the dilated anterior segment of the left vestibule. We analyzed spray transport in the left maxillary sinus for multiple release conditions. Similar release points, localized on an approximately 2 mm × 4.5 mm contour, facilitated improved maxillary deposition in all 3 test cases. This suggests functional redundancy of nozzle insertion in a 3D numerical model for identifying the optimal spray release locations.

Deep neural networks for texture classification-A theoretical analysis.

We investigate the use of Deep Neural Networks for the classification of image datasets where texture features are important for generating class-conditional discriminative representations. To this end, we first derive the size of the feature space for some standard textural features extracted from the input dataset and then use the theory of Vapnik-Chervonenkis dimension to show that hand-crafted feature extraction creates low-dimensional representations which help in reducing the overall excess error rate. As a corollary to this analysis, we derive for the first time upper bounds on the VC dimension of Convolutional Neural Network as well as Dropout and Dropconnect networks and the relation between excess error rate of Dropout and Dropconnect networks. The concept of intrinsic dimension is used to validate the intuition that texture-based datasets are inherently higher dimensional as compared to handwritten digits or other object recognition datasets and hence more difficult to be shattered by neural networks. We then derive the mean distance from the centroid to the nearest and farthest sampling points in an n-dimensional manifold and show that the Relative Contrast of the sample data vanishes as dimensionality of the underlying vector space tends to infinity.

Deploying a quantum annealing processor to detect tree cover in aerial imagery of California.

Quantum annealing is an experimental and potentially breakthrough computational technology for handling hard optimization problems, including problems of computer vision. We present a case study in training a production-scale classifier of tree cover in remote sensing imagery, using early-generation quantum annealing hardware built by D-wave Systems, Inc. Beginning within a known boosting framework, we train decision stumps on texture features and vegetation indices extracted from four-band, one-meter-resolution aerial imagery from the state of California. We then impose a regulated quadratic training objective to select an optimal voting subset from among these stumps. The votes of the subset define the classifier. For optimization, the logical variables in the objective function map to quantum bits in the hardware device, while quadratic couplings encode as the strength of physical interactions between the quantum bits. Hardware design limits the number of couplings between these basic physical entities to five or six. To account for this limitation in mapping large problems to the hardware architecture, we propose a truncation and rescaling of the training objective through a trainable metaparameter. The boosting process on our basic 108- and 508-variable problems, thus constituted, returns classifiers that incorporate a diverse range of color- and texture-based metrics and discriminate tree cover with accuracies as high as 92% in validation and 90% on a test scene encompassing the open space preserves and dense suburban build of Mill Valley, CA.

Compulsive buying: an overlooked entity.

Compulsive buying is an under-recognised entity among Indian psychiatrists. A Medline search, hand searching of journals and direct communications with lead investigators in compulsive buying have generated numerous studies. Overseas data indicate a community prevalence between 1% and 8% . The phenomenon can be an independent entity or appears as a comorbidity with another axis I or axis II disorder. A degree of suspicion on part of clinician regarding its possible presence is the key to its detection. A few rating instruments are available to quantify the morbidity and screening for compulsive buying. Management involves pharmacotherapy with SSRIs, psychotherapy, self-help groups and self-help books. Epidemiological and clinical studies on compulsive buying should be undertaken by Indian psychiatrists to provide better services for people suffering from compulsive buying.

Is genetically modified crop the answer for the next green revolution?

Post-green revolution advances made in biotechnology paved the way of cultivating the high-yielding, stress and disease resistant genetically modified (GM) varieties of wheat, rice, maize cotton and several other crops. The recent rapid commercialization of the genetically modified crops in Asia, Americas and Australia indicates the potentiality of this new technology. GM crops give higher yields and are rich in nutritional values containing vitamins and minerals and can thus can help to alleviate hunger and malnutrition of the growing population in the under developed and developing countries. It could also be possible to develop more biotic and abiotic stress resistant genotypes in these crops where it was difficult to develop due to the unavailability of genes of resistance in the crossing germplasms. However, further research and investigations are needed to popularize the cultivation of these crops in different parts of the world. This review provides an insight of the impact of GM crops on contemporary agriculture across the past few decades, traces its' history across time, highlights new achievements and breakthroughs and discusses the future implication of this powerful technology in the coming few decades.