Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons

We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.     

A multi-criteria approach to identify favorable areas for goat production systems in Veracruz,México

This research identifies favorable areas for goat production systems in the state of Veracruz, Mexico. Through the use of the analytic hierarchy process, layers of biophysical and soil information were combined to generate a model of favorability. Model validation was performed by calculating the area under the curve, the true skill statistic, and a qualitative comparison with census records. The results showed the existence of regions with high (4494.3 km²) and moderate (2985.8 km²) favorability, and these areas correspond to 6.25 and 4.15%, respectively, of the state territory and are located in the regions of Sierra de Huayacocotla, Perote, and Orizaba. These regions are characterized as mountainous and having predominantly temperate-wet or cold climates, and having montane mesophilic forests, containing pine, fir, and desert scrub. The reliability of the distribution model was supported by the area under the curve value (0.96), the true skill statistic (0.86), and consistency with census records.     

Antimicrobial resistance and virulence profile of enterococci isolated from poultry and cattle sources in Nigeria

This study investigated the occurrence, antimicrobial resistance and virulence of Enterococcus from poultry and cattle farms. Three hundred and ninety samples: cloacal/rectal swabs (n?=?260) and manure (n?=?130] were processed for recovery of Enterococcus species. Standard bacteriological methods were used to isolate, identify and characterize Enterococcus species for antimicrobial susceptibility and expression of virulence traits. Detection of antibiotic resistance and virulence genes was carried out by polymerase chain reaction. Enterococcus was recovered from 167 (42.8%) of the 390 samples tested with a predominance of Enterococcus faecium (27.7%). Other species detected were Enterococcus gallinarum, Enterococcus faecalis, Enterococcus hirae, Enterococcus raffinosus, Enterococcus avium, Enterococcus casseliflavus, Enterococcus mundtii and Enterococcus durans. All the isolates tested were susceptible to vancomycin, but resistance to tetracycline, erythromycin, ampicillin and gentamicin was also observed among 61.0, 61.0, 45.1 and 32.7% of the isolates, respectively. Sixty (53.1%) of the isolates were multidrug resistant presenting as 24 different resistance patterns with resistance to gentamicin-erythromycin-streptomycin-tetracycline (CN-ERY-STR-TET) being the most common (n?=?11) pattern. In addition to expression of virulence traits (haemolysin, gelatinase, biofilm production), antibiotic resistance (tetK, tetL, tetM, tetO and ermB) and virulence (asa1, gelE, cylA) genes were detected among the isolates. Also, in vitro transfer of resistance determinants was observed among 75% of the isolates tested. Our data revealed poultry, cattle and manure in this area are hosts to varying Enterococcus species harbouring virulence and resistance determinants that can be transferred to other organisms and also are important for causing nosocomial infection.     

Importance of forest buffers for preserving soil carbon and nutrient stocks in farmed landscapes along two river sites in the savannas of the Volta basin,Ghana

Understanding the impacts of agricultural land use is desired for proper management of riparian forests buffers (RFs) in savannas. In this light, we analyzed the relationship between woody plant diversity and soil properties of RFs in farmlands (FAs) and protected areas (PAs) along Afram (Guinean zone) and Tankwidi (Sudanian zone) Rivers located within the Volta sub-basin of Ghana. ALOS-AVNIR imageries were used to map RFs to facilitate sampling of soil and woody vegetation (dbh ≥5?cm) using stratified randomized design (72 plots; size: 500?m² each) for the analysis of soil physical and chemical properties and Shannon-Wiener plant species diversity. Although the fractions of sand, silt, and clay varied between the PAs and FAs, they were predominantly categorized as sandy loam. Along the Afram River, there were no significant differences in the concentrations and nutrient stocks of soil C, N, P, and K as well as the pH, moisture content, and bulk density between PA and FA. For the Tankwidi River, the concentrations and nutrient stocks of C and K significantly decreased from PA to FA while N, P, pH, bulk density, and moisture content were not different. Of the soil attributes measured C, N, P, pH, ground slope, and soil moisture had significant relationships with the diversity and density of the riparian woody plants. Controlling agricultural activities in riparian forests could preserve soil properties similar to that found in protected areas.     

Influence of Cocoa Pod Husk-Based Compost on Nutrient Uptake of Okra (Abelmoschus esculentus (L.) MOENCH) and soil properties on an Alfisol

This experiment evaluated the potentials of cocoa pod husk (CPH)-based compost on okra and soil chemical properties. Three CPH-based compost: CPH+ Neem leaf (CPH+ NL), CPH+ Poultry manure (CPH+ PM) and CPH+ PM+ NL were prepared. The treatments; 25, 50, 75, 100 kg N/ha of each compost and NPK mineral fertilizer at 40, 50, 60 kg N/ha and control, were applied to 5 kg soil each and arranged in a completely randomized design in three replicates. Two varieties of okra (NH47-4 and LD88) were grown for six weeks and residual effect evaluated. The Nitrogen, Phosphorus, and Potassium uptake of okra were determined. Pre- and post-cropping soil analyses were done. Data were analyzed using ANOVA and means separated by Duncan Multiple Range Test at α_0.05. The results showed that the nutrient uptake of okra consistently increased with CPH-based compost compared to control in both main and residual cropping. Nitrogen uptake ranged from 53.6 (60 kg N/ha NPK) to 106.7 (50 kg N/ha CPH+ PM) and 16.10 (50 kg N/ha NPK) to 55.06 (25 kg N/ha CPH+ PM+ NL); Phosphorus uptake ranged from 6.9 (25 kg N/ha CPH+ NL) to 24.1 (60 kg N/ha NPK) and 3.70 (25 kg N/ha CPH+ NL) to 9.98 (50 kg N/ha CPH+ PM+ NL), while potassium uptake ranged from 166.4 (25 kg N/ha CPH+ NL) to 244.48 (25 kg N/ha CPH+ PM+ NL) and 64.06 (40 kg N/ha NPK) to 122.29 (75 kg N/ha CPH+ NL) mg/plant in main and residual cropping, respectively. Organic carbon, pH, nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg) and sodium (Na) were also significantly increased by the CPH-based compost. It could, therefore, be concluded that CPH-based compost could be a good fertilizer for okra production.     

Rehabilitation practices that shape cocoa agroforestry systems in Central Cameroon: key management strategies for long-term exploitation

In Africa’s main cocoa producing countries, rehabilitation of old cocoa orchards is increasingly debated but rarely adopted. In Central Cameroon, rehabilitation practices are regularly set up in old cocoa-based agroforestry systems (cAFS). To better understand the impact of such practices we built a chronosequence of 40 cAFS. We carried out specific surveys with farmers on each plot in order to check for rehabilitation effects on cocoa stands and associated woody species (AWS). We found that cocoa trees represented on average 88.2% of woody individuals and increased with age (from 84.7 to 91.5%). The cocoa stand basal area (BA) share significantly increased with age and reached up to 40.2% in the oldest systems. Cocoa, fruit and forest trees mean BA increased with aging. They were on average of 6.5, 5.7 and 10.7 m² ha^?1 respectively. Six different architectural types, different from the theoretical architectural evolution of cocoa trees over time, were identified. Among them, type 4 characterized by several orthotropic suckers of differing ages, was found typical of farmers’ cutting back practices. Type 4 cocoa trees density increased over time and its BA represented on average 60% of cocoa stand BA in the oldest systems. Concomitantly, farmer’s management of AWS led to continuous evolution of the systems both in terms of density and species composition. Our results show that (i) permanent densification and cutting back practices (type 4) allow the rejuvenation of cocoa stands while increasing cocoa stands BA share; (ii) the continuous management of AWS by farmers is undertaken to favour cocoa trees share over time by limiting inter-specific competition and promoting complementarity between cocoa trees and AWS. We argue that such practices explain a fair part of the long-term sustainability observed in cAFS from Central Cameroon and represent a model from which new rehabilitation schemes could be inspired.     

Structural Properties of Starch in Bread and Bread Model Systems: Influence of an Antistaling α‐Amylase

The influence of an antistaling α‐amylase on bread crumb and on wheat starch gels was investigated taking into account different levels of structural hierarchy. Bread was prepared by a conventional baking procedure. Starch gels were produced by heating a concentrated starch dispersion in closed molds. Bread and starch gels were characterized by compression tests, light microscopy (LM), differential scanning calorimetry, and X‐ray measurements. The α‐amylase enhanced the initial firmness of starch gels and reduced the firming rate of bread and starch gels on aging. LM revealed that amylose and amylopectin phase‐separated within the starch granules and that freshly baked control bread and starch gels showed weak birefringence which became more intense during aging. Amylase‐containing bread and starch gels exhibited strong birefringence in the amylose rich region of the granules directly after baking which did not significantly increase during aging. The enzyme hindered the retrogradation of amylopectin as detected by differential scanning calorimetry, whereas X‐ray diffraction indicated that the enzyme induced low levels of starch crystallinity which did not change during aging. It is hypothesized that the antistaling effect of the amylase is based on the capacity to partially degrade amylopectin and, by this, to hinder its recrystallization. On the other hand, the enzyme slightly degrades amylose by an endo‐mechanism which, in turn, promotes the rapid formation of a partly crystalline amylose network in fresh bread and hinders amylose rearrangements during aging.     

Effect of coffee husk and cocoa pods biochar on phosphorus fixation and release processes in acid soils from West Cameroon

Acid soil in West Cameroon has limited phosphorus (P) availability which limits plant growth. This is mainly because of low pH, high levels of exchangeable aluminium (Al) and iron (Fe) and fixation of P. In this study, acid soils, sampled in Bafang, were amended with biochar produced from coffee husks (CH) and cocoa pod husks (CP) at two different temperatures (350 and 550 °C) in other to evaluate the effect on the physicochemical properties of the acid soil and the effect on P sorption and desorption. The soil was amended with biochar at a rate of 0, 20, 40 and 80 g/kg and incubated for 7 and 60 days. Physicochemical properties of all soil–biochar samples were determined followed by sorption experiments and data fitted in the Langmuir and Freundlich isotherm models in other to evaluate soil P sorption capacity and its affinity to soil amended with biochar. Moreover, desorption studies were done to evaluate the availability of P in soil amended with biochar after sorption. The outcomes of this study reveal an increase in soil pH, electrical conductivity (EC), available P, soil organic carbon and a drastic decrease in exchangeable Al and Fe. The point of zero charge of biochar-amended soil was higher than the control and increased with amendment rate. The experimental data of the sorption of P on soils and soil–biochar samples fits into Langmuir and Freundlich models (R² > 0.9) suggesting that the P adsorption is controlled by both model mechanisms. Soil–biochar mixture results in a decrease in the sorption capacity as compared with the control and the decrease was predominant with increasing amendment rate. At amendment rates of 20, 40 and 80 g/kg after 7 days of incubation, $Q_{\max }$ for SCH350 were 2267, 2048 and 1823 mg/kg which increased to 2407, 2112 and 1990 mg/kg after 60 days of incubation. This tendency was observed for all biochar inputs with respect to the increase in incubation days. Furthermore, desorption of P from soil–biochar mixtures was enhanced with biochar added at greater rate and produced at higher temperature. The desorption percentage was increased by more than around 10% for all biochar types from 20 mg/kg to 80 mg/kg amendment. Thus, biochar addition to acid soils reduces P fixation to acid soil and improves P desorption to soil solution, thereby providing more available P in the soil solution and better conditions for plant growth.