Stalk rot species diversity and molecular phylogeny associated with diseased maize in India.

Stalk rot disease is a major constraint in maize production and till date reported to be caused by two to three species of phytopathogenic fungi but, in our present study, we disclose the first report of stalk rot is caused by complex species of phytopathogens, which belongs to five different genera. Therefore, to substantiate these findings, a total of 105 diseased samples of maize were collected from 21 different locations in six different geographical locations of India from which 48 isolates were used for the research study. Morphological features such as pigmentation, colony color, type of mycelium and pattern of mycelium was examined using macro and microscopic methods. A total of 11 different spp. of pathogens belonging to the five different genera: Fusarium verticillioides (56.25%), F. equiseti (14.5%), F. andiyazi (6.25%), F. solani (2.08%), F. proliferatum (2.08%), F. incarnatum (2.08%), Lasidioplodia theobrame (6.25%), Exserohilum rostrtum (4.16%), Nigrospora spp. (4.16%). and Schizophyllum commune (2.08%) were identified by different housekeeping genes (ITS, TEF-1α, RPB2 and Actin). Fusarium verticillioides, F. equiseti and F. andiyazi were major pathogens involved in stalk rot. This is the first report on F. proliferatum, F. solani, F. incarnatum, Lasidioplodia theobrame, Exserohilum rostrtum, Nigrospora spp. and Schizophyllum commune causing stalk rot of maize and their distribution in the different states of India. Studies on population dynamics of PFSR will enhance the understanding of pathogen behavior, virulence, or its association with different pathogens across India, which will facilitate the development of resistant maize genotypes against the PFSR.

Transit time estimation of drying springs in Uttarakhand region using environmental tritium concentration.

Many parts of the Uttarakhand state, situated in the hilly terrain of the Himalayan region of India are facing acute water crisis due to the drying up of the perennial springs which are the only source of potable water in those regions. Tritium (3H), the radioactive isotope of hydrogen (half-life of 12.32 years) and also a part of water molecule (in the form of HTO) acts as a very useful tracer in estimating the transit time of the hydrological systems. Tritium concentrations of three springs (S-1, S-2 and S-3) were monitored consecutively for three years (2017-2019) to better constrain the transit time estimation. The tritium concentrations of the springs are found to vary between 3.66 and 4.15 TU. All the springs show gradual decrease in tritium concentration with the passage of time indicating the diminishing percentage of freshly recharged modern water component. Among various lumped parameter models, the piston-flow model (PFM), exponential mixing model (EMM), exponential piston-flow model (EPM) and partial exponential mixing model (PEM) have been employed in this study. The historical record of weighted mean concentration of tritium in precipitation available for the Uttarakhand region is taken as input function in the modelling procedure. The application of various LPMs (PFM, EMM, EPM and PEM) indicates that the transit time of the S-1 spring ranges from 1.26 to 1.46 years whereas for S-2 spring, the transit time is found to vary from 5 months to 1.1 years. The MTT of S-3 spring ranges from 5 months to 11 months. The relatively short residence time of these springs indicates the actively recharged system. The estimation of accurate transit time is thus very crucial for understanding the renewability of the spring water systems.

Morphological characterization, pathogenicity screening, and molecular identification of Fusarium spp. isolates causing post-flowering stalk rot in maize.

Post flowering stalk rot (PFSR) of maize caused by the Fusarium species complex is a serious threat to maize production worldwide. The identification of Fusarium species causing PFSR based on morphology traditionally relies on a small set of phenomic characteristics with only minor morphological variations among distinct Fusarium species. Seventy-one isolates were collected from 40 sites in five agro-climatic zones of India to assess the diversity of Fusarium spp. associated with maize crops showing symptoms of PFSR in the field. To investigate the pathogenicity of Fusarium spp. causing PFSR sixty isolates were toothpick inoculated between the first and second node at 55 days after sowing during the tassel formation stage of the crop in Kharif (Rainy season), and Rabi (Winter season) season field trials. Ten most virulent Fusarium isolates, based on the highest observed disease index, were identified by homology and phylogenetic analyses of partial sequences of the translation elongation factor 1 α (Tef-1α). Based on morphological traits such as mycelial growth patterns and mycelial pigmentation, Fusarium isolates were divided into nine clusters. The isolates were judged to be virulent based on their ability to decrease seedling vigour in in-vivo situations and high disease severity in field experiments. Pathogenicity test during the Kharif season showed 12 isolates with virulent disease symptoms with a mean severity ranging between 50 to 67 percent disease index (PDI) whereas in Rabi season, only five isolates were considered virulent, and the mean severity ranged between 52 to 67 PDI. Based on pathological characterization and molecular identification, 10 strains of Fusarium species namely, Fusarium acutatum (2/10), Fusarium verticillioides (Syn. Gibberella fujikuroi var. moniliformis) (7/10), Fusarium andiyazi (2/10) recorded the highest diseases index. All these species are part of the Fusarium fujikuroi species complex (FFSC). The distribution of virulent isolates is specific to a geographical location with a hot humid climate. Increased knowledge regarding the variability of Fusarium spp. responsible for PFSR of maize occurring across wide geographical locations of India will enable more informed decisions to be made to support the management of the disease, including screening for resistance in maize-inbred lines.

Investigation of aqueous phase dynamics in a uranium stripping unit using radioactive tracer.

Mixer-setters units are widely used in uranium purification processes. For efficient operations of mixer-settler units, it is essential to measure the hydrodynamics parameters of the different phases involved. The residence time distribution (RTD) measurement is commonly used method to estimate the hydrodynamics parameters of process reactors. In the present study, RTD of the aqueous phase was measured in different stages mixer-settler unit (mixers, settlers and mixer-settler units) used for stripping operation using Iodine-131 as a radiotracer. For the RTD measurements, radiotracer was injected as an impulse in aqueous phase feed line and its movement was monitored at different locations in the stripping unit using NaI(Tl) detectors. The mean residence times (MRTs) of the aqueous phase were estimated from measured RTD curves. For quantification of the degree of mixing, suitable flow models were proposed based on design and nature of the measured RTD curves and subsequently used for simulation. Based on the results of the RTD study, the mixing of aqueous phase was characterized and design of the stripping unit and its sub-units were validated. The optimum conditions were identified for efficient for the operation of the stripping unit.

Chemistry beyond the Hartree-Fock energy via quantum computed moments.

Quantum computers hold promise to circumvent the limitations of conventional computing for difficult molecular problems. However, the accumulation of quantum logic errors on real devices represents a major challenge, particularly in the pursuit of chemical accuracy requiring the inclusion of electronic correlation effects. In this work we implement the quantum computed moments (QCM) approach for hydrogen chain molecular systems up to H[Formula: see text]. On a superconducting quantum processor, Hamiltonian moments, [Formula: see text] are computed with respect to the Hartree-Fock state, which are then employed in Lanczos expansion theory to determine an estimate for the ground-state energy which incorporates electronic correlations and manifestly improves on the direct energy measurement. Post-processing purification of the raw QCM data takes the estimate below the Hartree-Fock energy to within 99.9% of the exact electronic ground-state energy for the largest system studied, H[Formula: see text]. Calculated dissociation curves indicate precision at about 10mH for this system and as low as 0.1mH for molecular hydrogen, H[Formula: see text], over a range of bond lengths. In the context of stringent precision requirements for chemical problems, these results provide strong evidence for the error suppression capability of the QCM method, particularly when coupled with post-processing error mitigation. While calculations based on the Hartree-Fock state are tractable to classical computation, these results represent a first step towards implementing the QCM method in a quantum chemical trial circuit. Greater emphasis on more efficient representations of the Hamiltonian and classical preprocessing steps may enable the solution of larger systems on near-term quantum processors.

Change in task conditions leads to changes in intermittency in intermittent feedback control employed by CNS in control of human stance.

Event-driven intermittent feedback control is a form of feedback control in which the corrective control action is only initiated intermittently when the variables of interest exceed certain threshold criteria. It has been reported in the literature that the CNS uses an event-driven intermittent control strategy to stabilize the human upright posture. However, whether the threshold criteria may change under different postural task conditions is not yet well understood. We employ a numerical study with inverted pendulum models and an experimental study with 51 young healthy individuals (13 females and 38 males; age: 27.8 ± 6.5 years) with stabilogram-diffusion, temporal and spectral analysis applied to COP (Center of Pressure) trajectories measured from these experiments to examine this aspect. The present study provides compelling evidence that inducing a natural arm swing during quiet stance appears to lead to higher sensory dead zone in neuronal control reflecting higher intermittency thresholds in active feedback control and a corresponding lower sensory dependence. Beyond the obvious scientific interest in understanding this aspect of how CNS controls the standing posture, an investigation of the said control strategy may subsequently help uncover insights about how control of quiet stance degrades with age and in diseased conditions. Additionally, such an understanding will also be of interest to the humanoid robotics community as it may lead to insights leading to improving control strategies for posture control in robots.

Residence time distribution study in a pilot-scale liquid phase catalytic exchange (LPCE) column packed with a mixture of hydrophobic and hydrophilic catalysts.

Residence time distribution (RTD) measurements were carried out in a packed bed column designed for exchange of hydrogen isotopes. The main objective of the study was to characterize the liquid phase mixing under various processes and operating conditions. The packed bed was composed of a mixture of two different types of catalytic packing materials, i.e., a hydrophobic material and a hydrophilic material. Technitium-99m (99mTc) as sodium pertechnetate was used as a radiotracer for RTD measurements. From the measured RTD curves, mean residence times (MRTs), liquid holdup and degree of mixing of liquid phase were evaluated. An axial dispersion model exchange with stagnant zones was used to simulate the measured RTD curves. The results of model simulation showed that volume fraction of hydrophobic to hydrophilic packing and gas/liquid superficial velocities affect the liquid holdup, bed pressure drop and liquid phase dispersion/mixing characteristics. The results of the present study will help to screen packing, optimize the volume of the packing fractions, design and construct the catalyst and optimize the operating conditions for scale up of the isotope exchange process.

Explaining Parkinsonian postural sway variabilities using intermittent control theory.

Postural impairment due to neuro-degenerative disorders such as Parkinson's Disease (PD) leads to restricted gait patterns, fall-related injuries, decreased mobility, and loss of functional independence. Though several clinical and posturographic studies have attempted to reveal the complex pathophysiology involved in PD, the diversity of Parkinsonian population makes them unclear and sometimes even contradictory. For instance, studies related to the Center of Pressure (CoP) sway during quiet stance in PD patients highlight both increase and reduction of magnitude in contrast to age-matched healthy individuals. A possible explanation for this contradiction is presented in this article. While the presence of intermittent control has been observed in postural control in human quiet stance, we hypothesize that one of the factors that affects postural instability in PD might be the increase in intermittency in active feedback control. Using a simulation model representing the Anterior-Posterior dynamics of human quiet standing, the intermittent control strategy is first contrasted against continuous control strategy in terms of stability, energy efficiency and settling time, thus establishing the inherent advantages of an intermittent control strategy. Further, the ability of the intermittent control strategy to explain several clinical observations in PD is demonstrated. An experimental pilot study is also conducted to support the simulation study, and several body sway parameters derived from recordings of CoP are presented. The presented results are in close agreement with reported clinical observations and may also prove useful for the assessment of disease progression and future fall risk.

Investigation of flow dynamics of porous clinkers in a ball mill using technitium-99m as a radiotracer.

A radiotracer investigation was carried out in a ball mill of a cement plant in Kenya. Residence time distribution (RTD) of raw feed to the mill was measured using Technetium-99m adsorbed on the clinkers as a radiotracer. From the measured RTDs, solid holdup and mean residence times (MRTs) in the ball mill and associated separator were determined. The measured RTDs were modelled using axial dispersion model (ADM) and tank-in-series model both connected with a plug flow component in series. The results of the modelling indicated significant degree of backmixing within the ball mill and no axial mixing in the separator.

Evaluation of hydraulic performance of an anaerobic pond using radiotracer technique.

A radiotracer investigation was carried out in a wastewater stabilization pond using radiotracer technique. Residence time distribution (RTD) of wastewater was measured using Iodine-131 as a radiotracer. The measured RTD was treated and mean residence time (MRT) was determined. The measured MRT was compared with the theoretical MRT and dead volume was estimated. It was found that about 93% of the geometric volume within the anaerobic pond was dead. The measured RTD was modeled using various RTD models and eventually a suitable model was identified to describe and visualize the flow pattern of wastewater within the pond. Based on the measured MRT, estimated dead volume and identified flow patterns, it was concluded that the hydraulic performance of the anaerobic pond was very poor and not suitable for its intended purpose.

A Possible Explanation of How High-Frequency Deep Brain Stimulation Suppresses Low-Frequency Tremors in Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder of the central nervous system and one of its key symptoms is rest tremor. Deep brain stimulation (DBS) effectively suppresses rest tremor in Parkinson's disease. Despite being a successful treatment option, its underlying principle and the mechanism by which it attenuates tremors is not yet fully understood. Since existing methods for tuning DBS parameters are largely trial and error, understanding how DBS works can help to reduce time and costs, and could also ultimately lead to better treatment strategies for PD. In this paper, we set out to analyze how a high-frequency stimulation applied through DBS can help reduce the low-frequency rest tremors observed in PD patients. We identify key elements in the sensorimotor loop (the feedback loop consisting of sensory feedbacks and motor responses) that play a role in the interaction of high-frequency DBS signal and the low-frequency tremor. Based on the analysis of these elements, we draw insights about the working of DBS and the role of frequency and the nature of stimulation. We verify these observations with numerical examples and a bench top experimental example.

Effect of dynamic bias on accuracy of radioactive particle tracking (RPT) technique at different data acquisition frequencies.

The accuracy of radioactive particle tracking technique depends on the ability to locate the exact position of a tracer particle. In the current work, experiments are performed to find the accuracy of an RPT measurement in terms of locating the position of the tracer particle and its velocity measurement. Results are presented for different tracer velocities at different data acquisition frequencies to minimize the error generated due to dynamic bias. Finally an optimal frequency is recommended for different velocities of a tracer particle to achieve the best possible accuracy.

Measurement of residence time distribution of liquid phase in an industrial-scale continuous pulp digester using radiotracer technique.

A series of radiotracer experiments was carried out to measure residence time distribution (RTD) of liquid phase (alkali) in an industrial-scale continuous pulp digester in a paper industry in India. Bromine-82 as ammonium bromide was used as a radiotracer. Experiments were carried out at different biomass and white liquor flow rates. The measured RTD data were treated and mean residence times in individual digester tubes as well in the whole digester were determined. The RTD was also analyzed to identify flow abnormalities and investigate flow dynamics of the liquid phase in the pulp digester. Flow channeling was observed in the first section (tube 1) of the digester. Both axial dispersion and tanks-in-series with backmixing models preceded with a plug flow component were used to simulate the measured RTD and quantify the degree of axial mixing. Based on the study, optimum conditions for operating the digester were proposed.

Program directors' perceptions of importance of pediatric procedural skills and resident preparedness.

BACKGROUND: The Royal College of Physicians and Surgeons of Canada (RCPSC) objectives for training in pediatrics include 26 procedural skills, 11 of which are included in the final in-training evaluation report (FITER). The importance of each procedure for practice and the preparedness of pediatric residency graduates to perform these procedures are not known. METHODS: A questionnaire was distributed to all pediatric residency program directors and members of the RCPSC Specialty Committee in Pediatrics (N = 21) in October 2010, requesting them to rate the perceived importance and preparedness of graduating pediatric residents in all procedural skills on a 5 point Likert scale, as well as the presence of a curriculum and documentation for each procedure. Mean importance and preparedness were calculated for each procedure. RESULTS: Response rate was 16/21 (76 %). Perceived preparedness was significantly lower than importance for the majority of procedures (p < 0.05). Ten procedures had a high mean importance rating (>3) but a low mean preparedness rating (<3). Presence of a curriculum and documentation for procedures varied across centers, and their presence was correlated with both perceived importance and preparedness (p < 0.0001). CONCLUSIONS: Many procedures in which pediatric residents are required to be competent by the RCPSC are felt to be important. Residents are not felt to be adequately prepared in several of the required procedures by the time of graduation. Procedures with high ratings of importance but low preparedness ratings should be targeted for curricular interventions.

Simulation-based learning combined with debriefing: trainers satisfaction with a new approach to training the trainers to teach neonatal resuscitation.

BACKGROUND: Prompt initiation of appropriate neonatal resuscitation skills is critical for the neonate experiencing difficulty transitioning to extra-uterine life. The use of simulation training is considered to be an indispensable tool to address these challenges. Research has yet to examine the effectiveness of simulation and debriefing for preparation of trainers to train others on the use of simulation and debriefing for neonatal resuscitation. This study determines the degree to which experienced NRP instructors or instructor trainers perceived simulation in combination with debriefing to be effective in preparing them to teach simulation to other health care professionals. METHODS: Participants' perceptions of knowledge, skills, and confidence gained following a neonatal resuscitation workshop (lectures; scenario development and enactment; video recording and playback; and debriefing) were determined using a pre-post test questionnaire design. Questionnaire scores were subjected to factor and reliability analyses as well as pre- and post-test comparisons. RESULTS: A total of 17 participants completed 2 questionnaires. Principal component extraction of 18 items on the pre-test questionnaire resulted in 5 factors: teamwork, ability to run a simulation, skills for simulation, recognizing cues for simulation and ability to debrief. Both questionnaire scores showed good reliability (α: 0.83 - 0.97) and factorial validity. Pre- and post-test comparisons showed significant improvements in participants' perceptions of their ability to: conduct (as an instructor) a simulation (p < .05, η² .47); participate in a simulation (p < .05, η² .45); recognize cues (p < .05, η² .35); and debrief (p < .05, η² .41). CONCLUSIONS: Simulation training increased participants' perceptions of their knowledge, skills, and confidence to train others in neonatal resuscitation.

Leading educationally effective family-centered bedside rounds.

BACKGROUND: Family-centered bedside rounds (family-centered rounds) enable learning and clinical care to occur simultaneously and offer benefits to patients, health care providers, and multiple levels of learners. OBJECTIVE: We used a qualitative approach to understand the dimensions of successful (ie, educationally positive) family-centered rounds from the perspective of attending physicians and residents. METHODS: We studied rounds in a tertiary academic hospital affiliated with the University of Calgary. Data were collected from 7 focus groups of pediatrics residents and attendings and were analyzed using grounded theory. RESULTS: Attending pediatricians and residents described rounds along a spectrum from successful and highly educational to unsuccessful and of low educational value. Perceptions of residents and attendings were influenced by how well the environment, educational priorities, and competing priorities were managed. Effectiveness of the manager was the core variable for successful rounds led by persons who could develop predictable rounds and minimize learner vulnerability. CONCLUSIONS: Success of family-centered rounds in teaching settings depended on making the education and patient care aims of rounds explicit to residents and attending faculty. The role of the manager in leading rounds also needs to be made explicit.

Validating objectives and training in Canadian paediatrics residency training programmes.

BACKGROUND: Changing health care systems and learning environments with reduction in resident work hours raises the question: "Are we adequately training our paediatricians?" AIMS: (1) Identify clinical competencies to be acquired during paediatric residency training to enable graduates to practise as consultant paediatricians; (2) Identify gaps in preparedness during training and; (3) Review and validate competencies contained in the Royal College of Physicians and Surgeons of Canada (RCPSC) objectives of training (OTR) for paediatrics. METHODS: A questionnaire with 19 classification domains containing 92 clinical competencies was administered to RCPSC certified paediatricians who completed residency training in Canada from June 2004 to June 2008. For each competency, paediatricians were asked to indicate the importance and their degree of preparedness upon entering practice. Gap scores (GSs) between importance and preparedness were calculated. RESULTS: Response rate was 43% (187/435); 91.3% (84/92) of competencies in the RCPSC OTR were identified as important. Paediatricians felt less than adequately prepared for 25% (23/92) of competencies; 40 competencies had GSs >10%. CONCLUSIONS: The unique approach used in this study is useful in validating OTR as well as the preparation of residents in relation to OTR. The results indicate a potential need for additional training in specific competencies.

Neonatal ventricular tachyarrhythmias in medium chain acyl-CoA dehydrogenase deficiency.

We describe an unusually severe case of medium chain acyl-CoA dehydrogenase (MCAD) deficiency in a term female neonate, who presented at 12 h of age with lethargy, poor feeding, hypoglycemia and ventricular tachyarrhythmias. While arrhythmias are common in other disorders of fatty acid beta-oxidation, ventricular tachyarrhythmias have rarely been reported with MCAD deficiency in childhood. Since the results of newborn metabolic screening are usually not available within the first 3 days of life, our case highlights the need for health care professionals to be made aware of this early and uncommon but potentially fatal presentation of MCAD deficiency.

Neurodevelopmental outcomes of premature infants treated with l-arginine for prevention of necrotising enterocolitis.

AIM: This study aimed to compare the long-term neurodevelopmental outcomes at 36 months adjusted age in preterm infants (birth weight < or = 1250 gm) who received supplementation with L-arginine during the first 28 days of life with controls. METHODS: Surviving infants enrolled in a randomised control study of L-arginine supplementation were prospectively followed longitudinally to determine their neurodevelopmental outcomes at 36 months of adjusted age. Neurologic examination and neurodevelopmental assessments were performed by examiners who were unaware of the original treatment assignments. RESULTS: A total of 132 children (95% of survivors) were evaluated at 36 months adjusted age. In the group given L-arginine, 5 of 61 (8.1%) had major neurodevelopmental disabilities, defined as the presence of one or more of cerebral palsy, cognitive delay (cognitive index <70), bilateral blindness or bilateral hearing loss requiring hearing aids as compared with 9 of 71 (12.6%) in the placebo group (relative risk, 0.64; 95 % confidence interval, 0.22-1.82; P= 0.40). CONCLUSIONS: There is no increase in neurodevelopmental disability in preterm infants who received L-arginine supplementation.

Does necrotising enterocolitis impact the neurodevelopmental and growth outcomes in preterm infants with birthweight < or =1250 g?

AIM: To compare the long-term growth and neurodevelopmental outcomes at 36 months adjusted age in preterm infants (birthweight (BW) < or = 1250 g) with necrotising enterocolitis (NEC) with BW-matched controls. METHODS: This is a case control study performed at a regional tertiary care neonatal intensive care unit. Infants with stage II or III NEC admitted to a regional tertiary care neonatal unit between 1995 and 2000 were identified. Each infant with NEC was matched by BW (+/-100 g) to next two infants admitted in the unit without NEC. Growth and neurodevelopmental outcomes at 36 months are compared. RESULTS: In total, 51 infants with NEC and 102 controls met study eligibility criteria and 146/153 (94.3%) were prospectively followed for 36 months. Infants with NEC had more culture-proven sepsis (35.3% vs. 10.8%, P < 0.001); patent ductus arteriosus requiring therapy (64.7% vs. 45%, P = 0.02), chronic lung disease (60.7% vs. 45%, P = 0.04) and longer hospital stay (84 days vs. 71 days, P < 0.0001). There were no significant differences in growth outcomes between the two groups at 36 months. Overall 24% of infants with NEC had one major neurodevelopmental disability compared with 10% among control infants. Infants who developed NEC had significantly higher cognitive delay (i.e. cognitive index <70) and visual impairment. A logistic regression model identified NEC as a predictor of cognitive delay. CONCLUSION: Preterm infants who develop NEC are at a significantly higher risk for developing neurodevelopmental disability. We recommend close neurodevelopmental follow up for all < or =1250 g infants who develop stage II or III NEC.