Coupled land-atmosphere modeling of the effects of shrub encroachment on nighttime temperatures

Changes in vegetation cover affect the interactions between the land surface and the overlying atmosphere with important impacts on surface energy balance and microclimate conditions. A major ongoing change in vegetation cover has been observed in dryland regions around the world, where desert shrubs are encroaching into arid grasslands. However, the impact of shrub encroachment on local climate has not been investigated. We used a mesoscale model coupled with a Land Surface Model to simulate the effects of shrub encroachment on nighttime temperatures. These effects can have an important effect on the establishment of shrubs and need to be represented well by land surface parameterization schemes that are also used in long-term climate simulations. Idealized 2-dimensional simulations were conducted with vegetation types corresponding to shrubland and grassland typical of the Northern Chihuahuan Desert. Simulated surface energy and radiation fluxes and near-ground air temperature were analyzed and compared with observations. Results show a good comparison between the simulations and observations as long as vegetation parameters are adjusted in the model to be in better agreement with the observed parameters. The sensitivity of the nighttime air temperatures to green vegetation fraction, albedo, emissivity and roughness length is investigated. The results indicate that the green vegetation fraction is the key factor that causes the higher nighttime temperature in shrubland than in adjacent grassland, mainly by its effects on soil surface insulation, soil thermal diffusivity, and therefore on ground heat fluxes.     

Strategic use of Iranian bread wheat landrace accessions for genetic improvement: Core set formulation and validation

Iranian wheat landrace accessions (IWAs) were collected from country‐wide farm fields and market places in 1935 by a professor at the University of Tehran and shared with University of California at Davis, California. IWAs were further submitted to the genebank of International Maize and Wheat Improvement Center (CIMMYT), Mexico. 2,403 IWAs from CIMMYT’s genebank were assayed by DArT‐seq technology to assess genetic diversity. No apparent ecogeographic patterns related to genetic diversity were detected, probably due to long‐term transport and frequent interchange of landraces among farmers. A multivariate clustering procedure combining genotypic and phenotypic information was used in selecting a core‐set, which represented 15% of the hexaploid wheat accessions included in this study. This subset captured an estimated 93% of rare (frequency <0.05) alleles. Multisite phenotypic data (India, Mexico) validated the ability of the core‐set in detecting useful variants. Potential donor accessions for multiple traits (disease resistance, zinc concentration) were identified from the core‐set for wheat‐breeding. This report illustrates a breeder friendly robust core‐set formulation strategy for harnessing the useful genetic variation stored in the genebanks.     

Effects of dairy husbandry practices and farm types on raw milk quality collected by different categories of dairy processors in the Peruvian Andes

In developing countries, milk quality is often mismanaged in relation to husbandry practices, collection logistics, and the production of small batches. This paper investigates how the management of milk quality from farm to dairy processor impacts on both chemical and hygienic indicators, in a context characterized by farm scale diversity, the co-existence of formal and informal markets, and high milk demand. It is based on an analysis of the chemical and hygienic quality of milk samples collected over a 12-month period from 20 farms and three dairy processors. Data from the farmers’ husbandry practices and the logistics of milk collection were also collected. A large range of quality profiles and farming practices were observed. This diversity is explained by rainfall and temperature pattern, farm size which affects hygienic quality, and lack of efficient logistics between farms and dairy processors. The findings indicate that in a context of high demand for milk and poor private and public regulations, milk quality is impacted upon by poor stakeholders’ management practices.     

High fry production rates using post-thaw silver carp (Hypophthalmichthys molitrix) spermatozoa under farming conditions

Silver carp (Hypophthalmichthys molitrix) is not endemic to Cuba, and egg fertilization is totally artificial; males produce spermatozoa only between March and October. Cryopreservation of silver carp spermatozoa would reduce the number of males needed, minimize handling stress through less frequent stripping, and facilitate artificial propagation when eggs are available. The effects on motility and fry production from eggs fertilized with thawed sperm under farm-conditions were examined in this study. Five, seven and ten percent of dimethyl sulfoxide (DMSO), glycerol and methanol were tested as cryoprotectants. DMSO was a more suitable cryoprotectant than methanol or glycerol. The effect of equilibration time on the motility rate at 10% DMSO was evaluated. Hatching rates equal to the control (P>0.01) were obtained under farm conditions with frozen spermatozoa, stored even for a year in liquid nitrogen, with a final DMSO concentration of 10%. Cryopreservation offers a useful routine method for sperm storage and silver carp handling. To our knowledge, this is the first report on the production of fry from post-thaw silver carp spermatozoa under farming conditions.     

Estimating the Health Impact of Climate Change With Calibrated Climate Model Output

Studies on the health impacts of climate change routinely use climate model output as future exposure projection. Uncertainty quantification, usually in the form of sensitivity analysis, has focused predominantly on the variability arise from different emission scenarios or multi-model ensembles. This paper describes a Bayesian spatial quantile regression approach to calibrate climate model output for examining to the risks of future temperature on adverse health outcomes. Specifically, we first estimate the spatial quantile process for climate model output using non-linear monotonic regression during a historical period. The quantile process is then calibrated using the quantile functions estimated from the observed monitoring data. Our model also down-scales the gridded climate model output to the point-level for projecting future exposure over a specific geographical region. The quantile regression approach is motivated by the need to better characterize the tails of future temperature distribution where the greatest health impacts are likely to occur. We applied the methodology to calibrate temperature projections from a regional climate model for the period 2041 to 2050. Accounting for calibration uncertainty, we calculated the number of excess deaths attributed to future temperature for three cities in the US state of Alabama.     

Dissolved phosphorus composition of grassland leachates following application of dairy‐slurry size fractions

Appropriate management of P from slurry can increase crop production and decrease nutrient loss to water bodies. The present study examined how the application of different size fractions of dairy slurry influenced the quantity and composition of P leached from grassland in a temperate climate. Soil blocks were amended (day 0 = start of the experiment) with either whole slurry (WS), the > 425 μm fraction (coarse slurry fraction, CSF), the < 45 μm slurry fraction (fine liquid slurry fraction, FLF), or not amended, i.e., the control soil (CON). Deionized water was added to the soil blocks to simulate six sequential rainfall events, equivalent to 250 mm (day 0.2, 1.2, 4.2, 11.2) or 500 mm of rainfall (day 18.2 and 25.2), with leachates collected the following day. The results showed that total dissolved P (TDP), dissolved reactive P (DRP), dissolved unreactive P (DUP), orthophosphate, phosphomonoester, and pyrophosphate concentrations generally decreased with the increasing number of simulated rain events. Total dissolved P was leached in the following order WS > FLF ≈ CSF > CON. Dissolved organic C was correlated with TDP, DRP, and DUP in leachates of all treatments. The highest concentrations of dissolved phosphomonoesters and pyrophosphate (147 μg P L^–1 and 57 μg P L^–1, respectively) were detected using solution ³¹P‐NMR spectroscopy in the WS leachates. Overall, there were significant differences observed between slurry treatments (e.g., relative contributions of inorganic P vs. organic P of dissolved P in leachates). Differences were independent from the rate at which slurry P was applied, because the highest dissolved P losses per unit of slurry P applied were measured in the FLF, i.e., the treatment that received the smallest amount of P. We conclude that the specific particle‐size composition of applied slurry influences dissolved P losses from grassland systems. This information should be taken in account in farm‐management approaches which aim to minimizing dissolved slurry P losses from grassland systems.     

Plasma Cardiac Troponin I Concentration and Cardiac Death in Cats with Hypertrophic Cardiomyopathy

Background

The use of cardiac biomarkers to assist in the diagnosis of occult and symptomatic hypertrophic cardiomyopathy (HCM) in cats has been established. There is limited data describing their prognostic utility in cats with HCM.

Hypothesis

Circulating concentrations of N‐terminal B‐type natriuretic peptide (NTproBNP) and cardiac troponin I (cTnI) predict cardiac death in cats with HCM.

Animals

Forty‐one cats diagnosed with HCM at a veterinary teaching hospital, between February 2010 and May 2011.

Methods

Prospective investigational study. Plasma samples were collected from cats diagnosed with HCM and concentrations of NTproBNP and cTnI were analyzed at a commercial laboratory. Echocardiographic measurements from the day of blood sampling were recorded. Long‐term outcome data were obtained. Associations with time to cardiac death were analyzed using Cox proportional hazards models.

Results

When controlling for the presence/absence of heart failure and echocardiographic measures of left atrial size and function, cTnI > 0.7 ng/mL was independently associated with time to cardiac death. In univariable analysis, NTproBNP > 250 pmol/L was associated with cardiac death (P = .023), but this did not remain significant (P = .951) when controlling for the effect of clinical signs or left atrial size/function.

Conclusions and Clinical Importance

Plasma concentration of cTnI (cutoff >0.7 ng/mL) is a predictor of cardiac death in cats with HCM that is independent of the presence of heart failure or left atrial dilatation.     

Effect of treatment with atenolol on 5-year survival in cats with preclinical (asymptomatic) hypertrophic cardiomyopathy

ObjectivesTo investigate the effect of treatment with atenolol on 5-year survival in cats with preclinical hypertrophic cardiomyopathy (HCM).Animals63 Client-owned cats with preclinical HCM and 31 healthy control cats.MethodsProspective, observational, open-label, clinical cohort study. Cats with HCM were diagnosed by echocardiography, treated with atenolol (6.25–12.5 mg q12h, PO; n = 42) or untreated (n = 21), and were observed for 5 years after enrollment. The study end point was death from any cause. Cats of similar body weight, age, gender, and breed without evidence of heart disease were studied concurrently and served as controls.ResultsDuring the observational period, 27 cats with HCM died; 14 (22%) due to cardiac disease and 13 (21%) due to non-cardiac disease. Ten control cats (32%) died of non-cardiac disease. There was no significant difference (P = 0.307) in all-cause mortality between control and HCM. Cardiac mortality was higher in cats with HCM compared to control cats (P = 0.005). There was no significant difference in all-cause mortality (P = 0.729) and cardiac mortality (P = 0.897) between cats with HCM treated or untreated with atenolol. Age and left atrial size at diagnosis were the only predictors of 5-year outcome.ConclusionsOur study failed to demonstrate an effect of atenolol on 5-year survival in cats with preclinical HCM.     

The effect of supplementing layer diets with shark cartilage or chitosan on egg components and yolk lipids

1. An experiment was designed to evaluate the effects of the addition of shark cartilage (SC) or chitosan (CH) to layer diets on egg component weights, yolk lipids and hen plasma lipids. 2. Hy-Line laying hens (80) were used during a 56 d feeding trial. Treatments were: basal diet (BD), BD + 20 g/kg SC, BD + 30 g/kg SC, BD + 20 g/kg CH and BD + 30 g/kg CH. Eggs were analysed on d 14, 28, 42 and 56. 3. Egg weight and egg component weights were not affected by these treatments throughout the experimental period. 4. After 14d of experimental feeding, cholesterol levels were higher in eggs from birds given BD + 20 g/kg CH and BD + 30 g/kg CH than in those from birds given BD. 5. Furthermore, eggs from hens given BD + 20 g/kg SC or BD + 20 g/kg CH were higher in palmitic and stearic acids and lower in oleic acid than those from birds fed on BD. After 56 d feeding, however, palmitic and stearic acid contents in eggs from hens given any of the supplemented diets were lower than in those from hens given BD, and oleic acid in eggs from hens given BD + 20 g/kg SC, BD + 30 g/kg SC and BD + 30 g/kg CH was higher than in those from birds fed on BD. 6. Plasma cholesterol and triacylglycerol levels were not significantly affected by dietary treatment. 7. Shark cartilage or chitosan at up to 30 g/kg in layer diets did not affect egg component weights (yolk, white and shell) and total lipid contents. During the period from 42 to 56d of experimental feeding, diets containing up to 30 g/kg chitosan reduced egg yolk contents of cholesterol, palmitic and stearic acids and increased the content of oleic acid.