Precursor crop and vertisols type influences on teff (Eragrostis tef) response to fertilizer rates in the central highlands of Ethiopia

Optimization of fertilizer-N and -P is important to highland production of teff (Eragrostis tef) on Vertisols of central Ethiopia but may be affected by precursor crop and Vertisols type. On-farm experiments were conducted in three major teff growing districts of North Shewa (Moretina jiru, Ensaro, and Merhabete) in 2019 and 2020 with the main objectives was to determine the effect of precursor crops and Vertisols type on teff response to N and P rates. The N x P factorial combinations include 0, 60, 120, 180, and 240 kg N ha-1 and 0, 30, 60, and 90 kg P ha-1 applied each to light and heavy Vertisols with either cereal or pulse precursor crops in each district. In Merhabete, grain yield was significantly influenced by Pc x Vt x N and Pc x Vt x P but always with the lowest and highest grain yield with 0 and 240 kg N ha-1, respectively. Yield was 394 % more with 240 kg N ha-1 compared with no N and P applied. The Vt x Pc × N interaction affected teff yield in Moretina Jiru as application of 240 kg N ha-1 increased teff yield by 440 %, 30 %, 23 %, and 7 % on light Vertisols compared with 200 %, 16 %, 13 %, and 2 % on heavy Vertisols. The 4-way interaction of Vt x Pc x N x P affected grain yield in Ensaro due to the low N and P status of the soil coupled with the distinct Vertisols type in the district. In all districts, yield response to N was greater with pulse compared with cereal precursor crops and with a greater response for heavy compared with light Vertisols in Moretina Jiru and Ensaro. In Moretina Jiru, application of 170 kg-1N and soil maintenance level of 30 kg-1 of P ha-1 are recommended as an economic optimum rate (EOR). In Ensaro, the EOR for teff following cereal on light Vertisols are 166 kg N ha-1 and 65 kg P ha-1. At Ensaro, needed rates for teff following pulse on light Vertisols are 198 N ha-1 and 48 kg P ha-1. At Ensaro, needed rates for teff following cereal on heavy Vertisols are 240 N ha-1 and 90 kg P ha-1. At Ensaro, needed rates for teff following pulse on heavy Vertisols are 240 N ha-1 and 80 kg P ha-1. In Merhabete, the EOR for teff following cereal on light Vertisols are 182 kg N ha-1 and 60 kg P ha-1. In Merhabete, needed rates for teff following pulse on light Vertisols are 206 N ha-1 and 64 kg P ha-1. In Merhabete, needed rates for teff following cereal on heavy Vertisols are 240 N ha-1 and 90 kg P ha-1. In Merhabete, needed rates for teff following pulse on heavy Vertisols are 218 N ha-1 and 58 kg P ha-1. Therefore, those N and P rate are recommended for the study area, soil type and precursor crops.

Effects of phosphorus and sulfur on yield and nutrient uptake of wheat (Triticum aestivum L.) on Vertisols, North Central, Ethiopia

Deficiency of phosphorus (P) and sulfur (S) is increasingly being reported in soils of Ethiopia. While some studies have shown significant response of wheat to P and S application, information on the response of wheat to P and S application interactively is conspicuously lacking. In this regard, we evaluated the response of wheat to P and S application interactively in the study area. A field experiment was conducted at two locations to determine the effects of P and S, on yield, uptake and P, S use efficiency of bread wheat. A factorial combination of four levels of P (0,11,22 and 44 kg h⁻¹) and three levels S (0, 15 and 30 kg ha⁻¹) laid out in Randomized Complete Block Design with three replications. Results revealed that interacted application of P and S at 22 and 15 kg ha⁻¹ respectively increased grain yield of wheat by 40.1 % over control. The corresponding increase with straw was 53.4 % over control. Wheat yield obtained with combined application of P and S greater than single application of P or S indicating synergistic between them. The maximum grain N (56.3 kg ha-1), P (12.8 kg ha-1) and S (4.2 kg ha-1) uptakes were obtained due to combined application of P and S at 22 P and 15 S kg ha-1. Agronomic efficiencies of P and S decreased as the rates of P and S application increased. Combined fertilization of S and P is necessary in the study district and 15 kg S combined with 22 kg P ha⁻¹ produced the highest yield. Thus, this treatment is found to be recommended for bread wheat production in Vertisols of the district. While, partial budget analysis result revealed that, combination of 22P and 15S kg ha⁻¹ produced the highest MMR (54.9 %) and thus, this treatment is found to be economically feasible treatment for bread wheat production in study area of the district. We recommend further experiments on different combination of P with S in different agro-ecologies and soil types are required for confirmation of results and the residual effect of P and S on the following crop is needed to study the long-term effect of P and S.

[Evaluation of malaria rapid diagnostic test Optimal-IT® pLDH along the Plasmodium falciparum distribution limit in Mauritania]

Performance of the malaria Rapid Diagnostic Test (RDT) OptiMal-IT® was evaluated in Mauritania where malaria is low and dependent on a short transmission season. Slide microscopy was considered as the reference method of diagnosis. Febrile patients with suspected malaria were recruited from six health facilities, 3 urban and 3 rural, during two periods (December 2011 to February 2012, and August 2012 to March 2013). Overall, 780 patients were sampled, with RDT and thick blood film microscopy results being obtained for 759 of them. Out of 774 slides examined, of which 200 were positive, P. falciparum and P. vivax mono-infections were detected in 63.5% (127) and 29.5% (59), while P. falciparum/P. vivax coinfections were detected in 7% (14). Both species were observed in all study sites, although in significantly different proportions. The proportions of thick blood film and OptiMal-IT® RDT positive individuals was 26.3% and 30.3% respectively. Sensitivity and specificity of OptiMal-IT® RDT were 89% [95% CI, 84.7-93.3] and 91.1% [88.6-93.4]. Positives and negative predictive values were 78.1% [72.2-83.7] and 95.9% [94.1-97.5]. These diagnostic values are similar to those generally reported elsewhere, and support the use of RDTs as the main diagnostic tool for malaria in Mauritanian health facilities. In the future, choice of RDTs to be used must take account of thermostability in a hot, dry environment and their ability to detect P. falciparum and P. vivax.

Distributed electrode Mach-Zehnder modulator with double-pass phase shifters and integrated inductors

A novel high-speed Mach-Zehnder modulator (MZM) fully integrated into a 90 nm CMOS process is presented. The MZM features 'double-pass' optical phase shifter segments, and the first use of integrated inductors in a 'velocity-matched' distributed-electrode configuration.

Coupling modulation of microrings at rates beyond the linewidth limit

We demonstrate optical modulation rates exceeding the conventional cavity linewidth limit using a silicon coupling modulated microring. Small-signal measurements show coupling modulation was free of the parasitic cavity linewidth limitations at rates at least 6× the cavity linewidth. Eye diagram measurements show coupling modulation achieved data rates > 2× the rate attainable by conventional intracavity phase modulation. We propose to use DC-balanced encoding to mitigate the inter-symbol interference in coupling modulation. Analysis shows that coupling modulation can be more efficient than intracavity modulation for large output swings and high-Q resonators. Coupling modulation enables very high-Q resonant modulators to be simultaneously low-power and high-speed, features which are mutually incompatible in typical resonant modulators studied to date.

Inorganic mercury exposure in prairie voles (Microtus ochrogaster) alters the expression of toll-like receptor 4 and activates inflammatory pathways in the liver in a sex-specific manner

Environmental exposure to mercury can cause a number of adverse effects in humans including the disruption of endocrine function that may result in sex-specific effects. The present study was designed to characterize sex-specific effects of chronic inorganic mercury exposure on toll-like receptor (TLR) 2 and TLR4 and inflammatory signaling in the liver of prairie voles (Microtus ochrogaster). Following 10 weeks of exposure to mercury via drinking water, effects on protein expression levels of TLR2 and TLR4 and the downstream p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa (NF-κB) signaling pathways were assessed. Using immunoblot analysis, we found that mercury exposure significantly enhanced the expression of TLR4 and activated p38 MAPK and NF-κB pathways in vole livers. This is the first report indicating that TLR4 may serve as a sensor for chronic mercury exposure in the liver. Further, compared to females, mercury-treated male voles exhibited significant increases in activated p38 MAPK and a greater extent of liver damage. Together, these findings establish sex-specific liver immunomodulation and cellular signaling following chronic inorganic mercury exposure. Furthermore, this study also supports the use of voles as biomarkers of environmental mercury contamination and offers a promising in vivo tool to test various therapeutic strategies for mercury detoxification.

Interferon-beta induction by Chlamydia pneumoniae in human smooth muscle cells

Clinical studies have suggested a causal or contributory role of Chlamydia pneumoniae infection in asthma and atherosclerosis. The activation of synthetic functions of smooth muscle cells (SMC) including the production of cytokines and growth factors plays a major role in the formation of fibrous atherosclerotic plaques as well as in structural remodelling of the airway wall in chronic asthma. In this study we demonstrated that C. pneumoniae induced the production of low levels of interferon (IFN)-beta in bronchial and vascular SMC when infected cells were treated with tumour necrosis factor-alpha (TNF-alpha). IFN-beta production was analysed by reverse transcription-PCR and enzyme-linked immunosorbent assay. The upregulation of IFN-beta was paralleled by an increase in mRNA levels of interferon regulatory factor-1 and interferon-stimulated gene factor 3gamma, two transcription factors activating the expression of the IFN-beta gene. In addition, C. pneumoniae infection enhanced the mRNA level of indoleamine 2,3-dioxygenase, an IFN-inducible factor mediating the restriction of intracellular chlamydial growth, in TNF-alpha-stimulated SMC. C. pneumoniae-induced IFN-beta production by SMC may modulate inflammation and tissue remodelling during respiratory and vascular infection.

Treatment outcome among Rwandan and Burundian refugees with sputum smear-positive tuberculosis in Ngara, Tanzania

SETTING

Tuberculosis programme in six camps (Benaco, Musuhura, Lumasi, Lukole, Keza and Kitali) for Rwandan and Burundian refugees in Ngara district, Tanzania, where treatment was directly observed throughout.

OBJECTIVES

To evaluate the treatment outcome of sputum smear-positive tuberculosis cases recruited in refugee camps in Ngara, and to determine the cumulative frequency of conversion of sputum smears by direct microscopy.

DESIGN

Retrospective review of tuberculosis registers from January 1995 to December 1999.

RESULTS

Of 546 patients with smear-positive tuberculosis who were notified in the programme, 363 (66.5%) had completed treatment and were bacteriologically cured after 7 months, 10.9% had died, 7.1% had defaulted and 14.5% had transferred out. Sputum conversion after the 2-month intensive phase was 88%, and increased to 99% after 7 months of chemotherapy.

CONCLUSION

The involvement of the Tanzania NTLP in collaboration with health NGOs has led to a satisfactory outcome. These data suggest that it is possible for tuberculosis control programmes to perform successfully in refugee settings.

Diversity among Cynodon accessions and taxa based on DNA amplification fingerprinting

The genus Cynodon (Gramineae), comprised of 9 species, is geographically widely distributed and genetically diverse. Information on the amounts of molecular genetic variation among and within Cynodon taxa is needed to enhance understanding of phylogenetic relations and facilitate germplasm management and breeding improvement efforts. Genetic relatedness among 62 Cynodon accessions, representing eight species, was assessed using DNA amplification fingerprinting (DAF). Ten 8-mer oligonucleotides were used to amplify specific Cynodon genomic sequences. The DNA amplification products of individual accessions were scored for presence (1) or absence (0) of bands. Similarity matrices were developed and the accessions were grouped by cluster (UPGMA) and principal coordinate analysis. Analyses were conducted within ploidy level (2x = 18 and 4x = 36) and over ploidy levels. Each primer revealed polymorphic loci among accessions within species. Of 539 loci (bands) scored, 496 (92%) were polymorphic. Cynodon arcuatus was clearly separated from other species by numerous monomorphic bands. The strongest species similarities were between C. aethiopicus and C. arcuatus, C. transvaalensis and C. plectostachyus, and C. incompletus and C. nlemfuensis. Intraspecific variation was least for C. aethiopicus, C. arcuatus, and C. transvaalensis, and greatest for C. dactylon. Accessions of like taxonomic classification were generally clustered, except the cosmopolitan C. dactylon var. dactylon and C. dactylon var. afganicus. Within taxa, accessions differing in chromosome number clustered in all instances indicating the 2x and 4x forms to be closely related. Little, if any, relationship was found between relatedness as indicated by the DAF profiles and previous estimates of hybridization potential between the different taxa.