178 research outputs found
An Economic Analysis of Variable Rate Technology
Variable Rate Technology (VRT) offers an opportunity to improve production efficiency by allowing input applicationsto fluctuate in response to spatial variations in soil characteristics and nutrient levels. Society may also benefit fromreduced negative externalities, such as surface and groundwater contamination, from input applications. Using adynamic spatial model, this study examines how the interaction among variability, spatial autocorrelation, and meanlevel of soil fertility affects optimal sampling density and the economic gains from VRT. VRT was found to beprofitable under selected conditions, and the optimal grid size will vary with these conditions. In the case wherevariability and mean fertility levels are significantly high associated with low spatial autocorrelation, VRT producesgreater net returns than Uniform Rate Technology (URT), even with the smallest grid size to base the input applicationdecisions. Results also demonstrate that optimal grid size increases with increased spatial autocorrelation
On the Influence of ENSO on Sudden Stratospheric Warmings
Using the extended ERA5 reanalysis and three state-of-the-art models, this study explores how El Niño-Southern Oscillation (ENSO) can influence the total frequency, seasonal cycle and preconditioning of sudden stratospheric warmings (SSWs). Reanalysis data shows that in the last seven decades, winters with SSWs were more common than winters without, regardless El Niño (EN) or La Niña (LN) occurrence or the ENSO/SSW definitions. In agreement with previous studies, our models tend to simulate a linear ENSO-SSW relationship, with more SSWs for EN, around mid-winter (January–February) as in reanalysis, and less for LN when compared to neutral conditions. Independently of ENSO, the main tropospheric precursor of SSWs appears to be an anomalous wave-like pattern over Eurasia, but it is dominated by wavenumber 1 (WN1) for EN and shows an enhanced wavenumber 2 (WN2) for LN. The differences in this Eurasian wave pattern, which is largely internally generated, emerge from the distinct configuration of the background, stationary wave pattern induced by ENSO in the North Pacific, favoring a stronger WN1 (WN2) component during EN (LN). Our results suggest that the ENSO-forced signal relies on modulating the seasonal-mean polar vortex strength, becoming weaker and more displaced (stronger and more stable) for EN (LN), while ENSO-unforced wave activity represents the ultimate trigger of SSWs. This supports the view that ENSO and SSWs are distinct sources of variability of the winter atmospheric circulation operating at different time-scales and may reconcile previous findings in this context
AN ECONOMIC ANALYSIS OF VARIABLE RATE TECHNOLOGY
Variable Rate Technology (VRT) offers an opportunity to improve production efficiency by allowing input applicationsto fluctuate in response to spatial variations in soil characteristics and nutrient levels. Society may also benefit fromreduced negative externalities, such as surface and groundwater contamination, from input applications. Using adynamic spatial model, this study examines how the interaction among variability, spatial autocorrelation, and meanlevel of soil fertility affects optimal sampling density and the economic gains from VRT. VRT was found to beprofitable under selected conditions, and the optimal grid size will vary with these conditions. In the case wherevariability and mean fertility levels are significantly high associated with low spatial autocorrelation, VRT producesgreater net returns than Uniform Rate Technology (URT), even with the smallest grid size to base the input applicationdecisions. Results also demonstrate that optimal grid size increases with increased spatial autocorrelation.Keywords: spatial autocorrelation, spatial variability, variable rate technology
Family Communication in a Population at Risk for Hypertrophic Cardiomyopathy
Encouraging family communication is an integral component of genetic counseling; therefore, we sought to identify factors impacting communication to family members at risk for Hypertrophic Cardiomyopathy (HCM). Participants (N = 383) completed an online survey assessing: 1) demographics (gender, genetic test results, HCM family history, and disease severity); 2) illness representations; 3) family functioning and cohesiveness; 4) coping styles; 5) comprehension of HCM autosomal dominant inheritance; and 6) communication of HCM risk information to at‐risk relatives. Participants were a national sample of individuals with HCM, recruited through the Hypertrophic Cardiomyopathy Association. Data from 183 participants were analyzed using a logistic regression analysis, with family communication as a dichotomous dependent variable. We found that female gender and higher comprehension of autosomal dominant inheritance were significant predictors of participants’ communication of HCM risk information to all their siblings and children. Our results suggest that utilizing interventions that promote patient comprehension (e.g., a teaching‐focused model of genetic counseling) are important and may positively impact family communication within families with HCM.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147017/1/jgc40336.pd
Footrot and interdigital dermatitis in sheep: Farmer satisfaction with current management, their ideal management and sources used to adopt new strategies
The aims of this research were to identify management practices that sheep farmers currently use to treat and prevent footrot in sheep and whether they consider that these are successful management tools and to find out how sheep farmers would ideally like to manage footrot in their flock. Over 90% of lameness in sheep in the UK is caused by Dichelobacter nodosus, which presents clinically as interdigital dermatitis (ID) alone or with separation of hoof horn (FR). A questionnaire was sent to 265 farmers to investigate their current management and their satisfaction with current management of the spectrum of clinical presentations of footrot. Farmers were also asked their ideal management of footrot and their interest in, and sources of information for, change. Approximately 160 farmers responded. Farmers satisfied with current management reported a prevalence of lameness ≤5%. These farmers caught and treated lame sheep within 3 days of first seeing them lame, and treated sheep with FR and ID with parenteral antibacterials. Farmers dissatisfied with their management reported a prevalence of lameness >5%. These farmers practised routine foot trimming, footbathing and vaccination against footrot. Whilst 89% of farmers said they were satisfied with their management of FR over 34% were interested in changing management. Farmers identified veterinarians as the most influential source for new information. Farmers reported that ideally they would control FR by culling/isolating lame sheep, sourcing replacements from non-lame parents, trimming feet less, using antibacterial treatments less and using vaccination more. Footbathing was a commonly used management that was linked with dissatisfaction and that also was listed highly as an ideal management. Consequently, some of the ideal managements are in agreement with our understanding of disease control (culling and isolation, sourcing healthy replacements) but others are in contrast with our current knowledge of management and farmers self-reporting of satisfaction of management of footrot (less use of antibacterial treatment, more footbathing and vaccination). One explanation for this is the theory of cognitive dissonance where belief follows behaviour, i.e. farmers report that they believe an ideal which is what they are currently doing, even if the management is sub-optimal
El Niño teleconnection to the Euro-Mediterranean late-winter: the role of extratropical Pacific modulation
El Niño Southern Oscillation (ENSO) represents the major driver of interannual climate variability at global scale. Observational and model-based studies have fostered a long-standing debate on the shape and intensity of the ENSO influence over the Euro-Mediterranean sector. Indeed, the detection of this signal is strongly affected by the large internal variability that characterizes the atmospheric circulation in the North Atlantic–European (NAE) region. This study explores if and how the low-frequency variability of North Pacific sea surface temperature (SST) may impact the El Niño-NAE teleconnection in late winter, which consists of a dipolar pattern between middle and high latitudes. A set of idealized atmosphere-only experiments, prescribing different phases of the anomalous SST linked to the Pacific Decadal Oscillation (PDO) superimposed onto an El Niño-like forcing in the tropical Pacific, has been performed in a multi-model framework, in order to assess the potential modulation of the positive ENSO signal. The modelling results suggest, in agreement with observational estimates, that the PDO negative phase (PDO−) may enhance the amplitude of the El Niño-NAE teleconnection, while the dynamics involved appear to be unaltered. On the other hand, the modulating role of the PDO positive phase (PDO+) is not reliable across models. This finding is consistent with the atmospheric response to the PDO itself, which is robust and statistically significant only for PDO−. Its modulation seems to rely on the enhanced meridional SST gradient and the related turbulent heat-flux released along the Kuroshio–Oyashio extension. PDO− weakens the North Pacific jet, whereby favoring more poleward propagation of wave activity, strengthening the El Niño-forced Rossby wave-train. These results imply that there might be conditional predictability for the interannual Euro-Mediterranean climate variability depending on the background state
Seed set patterns in east African highland cooking bananas are dependent on weather before, during and after pollination
Open Access Journal; Published online: 29 Jun 2021Seed set in banana is influenced by weather, yet the key weather attributes and the critical period of influence are unknown. We therefore investigated the influence of weather during floral development for a better perspective of seed set increase. Three East African highland cooking bananas (EAHBs) were pollinated with pollen fertile wild banana ‘Calcutta 4′. At full maturity, bunches were harvested, ripened, and seeds extracted from fruit pulp. Pearson’s correlation analysis was then conducted between seed set per 100 fruits per bunch and weather attributes at 15-day intervals from 105 days before pollination (DBP) to 120 days after pollination (DAP). Seed set was positively correlated with average temperature (P < 0.05–P < 0.001, r = 0.196–0.487) and negatively correlated with relative humidity (RH) (P < 0.05–P < 0.001, r = −0.158–−0.438) between 75 DBP and the time of pollination. After pollination, average temperature was negatively correlated with seed set in ‘Mshale’ and ‘Nshonowa’ from 45 to 120 DAP (P < 0.05–P < 0.001, r = −0.213–−0.340). Correlation coefficients were highest at 15 DBP for ‘Mshale’ and ‘Nshonowa’, whereas for ‘Enzirabahima’, the highest were at the time of pollination. Maximum temperature as revealed by principal component analysis at the time of pollination should be the main focus for seed set increase
Association between Blood Pressure and HIV Status in Rural Uganda: Results of Cross-Sectional Analysis.
Introduction: The association between HIV status and hypertension is not well described within sub-Saharan Africa. We examined prevalence and risk factors for hypertension among HIV positive and negative individuals living in a rural district of Uganda. Methods: We conducted a cross-sectional analysis in two concurrent cohorts of 600 HIV negative and 721 HIV seropositive individuals aged ≥35 years. Results: Of the 721 HIV positive participants, 59.8% were women and the median age was 44.3 years, while for HIV negative individuals, 55% were women and the median age was 47.8 years. Over 90% of HIV positive individuals were on antiretroviral treatment. The prevalence of hypertension (≥140/≥90 mmHg) was 33.5% in HIV negative individuals and 23.9% in HIV positive individuals. Age (adjusted OR = 1.05, 95% CI 1.03 to 1.06) and BMI (adjusted OR = 1.08, 95% CI 1.05 to 1.12) were associated with higher odds of hypertension. Having HIV was associated with lower odds of hypertension (adjusted OR = 0.66, 95% CI 0.50 to 0.88), lower systolic blood pressure (-5.1 mmHg, 95% CI: -7.4 to -2.4) and lower diastolic blood pressure (-4.0 mmHg, 95% CI: -5.6 to -2.5). We did not observe differences in the odds of hypertension by CD4 count, viral load or ART among HIV positive individuals in this sample. Conclusions: Hypertension was prevalent in one third of HIV negative individuals and in one fourth of HIV positive patients. While access to health information among individuals attending HIV clinics may explain observed differences, more research is needed to understand plausible biological and social mechanisms that could explain lower blood pressure among people living with HIV in Uganda
Seed set patterns in east African highland cooking bananas show asymmetric distribution in bunches and fruits
Open Access Journal; Published online: 14 Apr 2021Low female fertility in bananas is the biggest hurdle for banana breeding. The aim of this study was to determine seed set patterns in East African Highland Cooking bananas (EAHBs) to inform future decisions on a more targeted approach of increasing seed set and subsequently banana-breeding efficiency. Matooke (AAA) and Mchare (AA) bananas are genetically distinct but belong to the same genetic complex, referred to as EAHBs. Seed set patterns in “Enzirabahima” (AAA), “Mshale” (AA), and “Nshonowa” (AA), all with residual fertility, were examined after hand pollination with a highly male fertile wild banana “Calcutta 4” (AA). Seed set in “Enzirabahima” is predominant in distal hands. Mchare cultivars have a slightly more even distribution of seeds in their hands compared to “Enzirabahima”. There is a gradual increase in seed set from proximal to distal hands with a slight drop in the last hand. This pattern is more definite in “Enzirabahima” and “Mshale”, while “Nshonowa” has a somewhat inconsistent pattern. There is also a drop in seed set per 100 fruits per hand from small to larger bunches. However, larger bunches have a higher pollination success compared to smaller bunches. They therefore set more seed on 100 fruits per hand and per bunch basis, if bunches without seed are accounted for. Pollination success rate increases from smaller to larger bunches of EAHBs. Seed set is biased toward the distal third part of fruits of examined EAHBs, as well as tetraploid Matooke hybrid “401K-1” (AAAA), and improved diploid “Zebrina” GF (AA) that were used for comparison. In comparison, in the highly female fertile “Calcutta 4”, seed set is along the entire length of the fruit. Seed set bias in the distal hands and distal end of fruits suggests a systematic mechanism rather than a random occurrence. It is expected that this information will provide a foundation for increased crossbreeding efficiency in bananas
- …