340 research outputs found
Climate Change and Plantation Agriculture: A Ricardian Analysis of Farmlands in Nigeria
This study used the Ricardian approach that captures farmer adaptations to varying environmental factors to analyze the impact of climate change (CC) on plantation agriculture in Nigeria. By collecting data from 280 farm households in seven different agro-ecological zones of Nigeria (Cross River, Abia, Edo, Ondo, Ekiti, Oyo and Ogun States), the quantity of crops produced over time and land value proxied by net revenue per hectares (NR), were regressed on climate, household and soil variables. The results suggest that these variables have a significant impact on the net crop revenue per hectare of farmlands under Nigerian conditions. Specifically, seasonal marginal impact analysis indicates that increasing temperature during summer and winter would significantly reduce crop net revenue per hectare whereas marginally increasing precipitation during spring would significantly increase net crop revenue per hectare. Furthermore, the net crop revenue impact of predicted climate scenarios from three models (CGM2, HaDCM3 and PCM) for the years 2020, 2060 and 2100 suggest drastic decline in future net revenue per hectare for plantation crops in Nigeria. However, these marginal impacts are not uniformly distributed across the different agro-ecological zones in Nigeria
Determinants of Volume of POME Generation in Palm Oil Mills for Planning Wastewater Recovery in Biogas Energy Development
Wastewater volume is a necessary prerequisite for planning transformation to valuable resource and averting environmental degradation. This study investigated the dynamics of POME volume generation in palm oil mills in relation to types of fresh fruit bunches (FFBs), seasons, milling scales and volume of crude palm oil (CPO) produced in ADAPALMS and catchment communities, Ohaji/Egbema LGA, Imo State. The eight catchment communities of ADAPALMS were categorised into three strata in relation to the number of small-scale mills in each community (1-5mills, 6-10mills, and 11-15mills). In each stratum, a community was randomly sampled. A total of nine small-scale mills were sampled from the three sampled communities (Ohoba, Amafor and Etekwuru) in proportion to the average number of mills in each stratum. The lone medium and large scale mill (ADAPLAMS) in the study area represented the other scales of milling. For small and medium scale mills, the volume of POME generated was measured from the dimensions of the vessels where POME was stored, while that of large scale mill was obtained from industrial records. Data was analysed using multiple linear regression of SPSS. The volume of POME generated is significantly related to milling scales and volume of CPO produced (p< 0.01); R2=0.788. Within small scale mills, the volume of POME is significantly related to types of FFBs (p< 0.01), different small milling scales (p< 0.05), and volume of CPO produced (p< 0.01); R2=0.762. Thus, these independent variables are the principal determinants of POME volume generation in the area. The result has implication on the necessity of predictive models in managing the dynamics of POME volumes for efficient recovery and transformation of the wastewater to bioenergy
Evaluating the Technical Efficiency of Hospitals in Southeastern Nigeria
Efficient utilization of health resources is a critical requirement for attaining health system goals particularly in low income countries. Inefficiency in health resource utilization may imply death for the next child in the queue in a resource constrained environment. This study analyzes the technical and scale efficiencies in hospitals in low income countries using Nigeria as a case study. The study uses primary data sample of 200 hospitals to estimate technical and scale efficiencies using the Data Envelopment Analysis (DEA). The results clearly indicate large variation in the efficiency of hospitals with average efficiency score of about 59% under the constant returns to scale assumption and about 72% under variable returns to scale. This raises some concerns about the level of technical and scale efficiencies in utilization of scarce health resources in the hospital sector particularly in low income countries
Nephromyces Represents a Diverse and Novel Lineage of the Apicomplexa That Has Retained Apicoplasts
A most interesting exception within the parasitic Apicomplexa is Nephromyces, an extracellular, probably mutualistic, endosymbiont found living inside molgulid ascidian tunicates (i.e., sea squirts). Even though Nephromyces is now known to be an apicomplexan, many other questions about its nature remain unanswered. To gain further insights into the biology and evolutionary history of this unusual apicomplexan, we aimed to 1) find the precise phylogenetic position of Nephromyces within the Apicomplexa, 2) search for the apicoplast genome of Nephromyces, and 3) infer the major metabolic pathways in the apicoplast of Nephromyces. To do this, we sequenced a metagenome and a metatranscriptome from the molgulid renal sac, the specialized habitat where Nephromyces thrives. Our phylogenetic analyses of conserved nucleus-encoded genes robustly suggest that Nephromyces is a novel lineage sister to the Hematozoa, which comprises both the Haemosporidia (e.g., Plasmodium) and the Piroplasmida (e.g., Babesia and Theileria). Furthermore, a survey of the renal sac metagenome revealed 13 small contigs that closely resemble the genomes of the nonphotosynthetic reduced plastids, or apicoplasts, of other apicomplexans. We show that these apicoplast genomes correspond to a diverse set of most closely related but genetically divergent Nephromyces lineages that co-inhabit a single tunicate host. In addition, the apicoplast of Nephromyces appears to have retained all biosynthetic pathways inferred to have been ancestral to parasitic apicomplexans. Our results shed light on the evolutionary history of the only probably mutualistic apicomplexan known, Nephromyces, and provide context for a better understanding of its life style and intricate symbiosis
Chlamydial contribution to anaerobic metabolism during eukaryotic evolution
The origin of eukaryotes is a major open question in evolutionary biology. Multiple hypotheses posit that eukaryotes likely evolved from a syntrophic relationship between an archaeon and an alphaproteobacterium based on H-2 exchange. However, there are no strong indications that modern eukaryotic H-2 metabolism originated from archaea or alphaproteobacteria. Here, we present evidence for the origin of H-2 metabolism genes in eukaryotes from an ancestor of the Anoxychlamydiales-a group of anaerobic chlamydiae, newly described here, from marine sediments. Among Chlamydiae, these bacteria uniquely encode genes for H-2 metabolism and other anaerobiosis-associated pathways. Phylogenetic analyses of several components of H-2 metabolism reveal that Anoxychlamydiales homologs are the closest relatives to eukaryotic sequences. We propose that an ancestor of the Anoxychlamydiales contributed these key genes during the evolution of eukaryotes, supporting a mosaic evolutionary origin of eukaryotic metabolism
Mentoring and Quality Service Delivery in Nigerian Public Universities: Does Organizational Culture Matter?
The study sought to investigate the effect of mentoring on quality service delivery in Nigerian public Universities by adopting the cross-sectional survey research design involving the administration of a questionnaire on a sample of 1900 respondents. The structural equation modelling was used to estimate the specified model. The results showed that supervisory mentoring and career development mentoring significantly affect quality service delivery. Similarly, peer review mentoring and role modelling significantly positively affect quality service delivery. Our study shows that organisational culture moderates the relationship between mentoring and quality service delivery. The study recommends that the management of Universities in Nigeria should institutionalise mentoring programmes to support employee career development and encourage senior employees to take on the responsibility of role modelling so that younger employees could emulate their work attitudes and improve the quality of service delivery in the institutions. The study’s result bears an important implication for public universities in Nigeria which must prioritize mentoring to foster the career growth of young faculty members and enhance quality service delivery
Real-world keystroke dynamics are a potentially valid biomarker for clinical disability in multiple sclerosis
Background:
Clinical measures in multiple sclerosis (MS) face limitations that may be overcome by utilising smartphone keyboard interactions acquired continuously and remotely during regular typing.
Objective:
The aim of this study was to determine the reliability and validity of keystroke dynamics to assess clinical aspects of MS.
Methods:
In total, 102 MS patients and 24 controls were included in this observational study. Keyboard interactions were obtained with the Neurokeys keyboard app. Eight timing-related keystroke features were assessed for reliability with intraclass correlation coefficients (ICCs); construct validity by analysing group differences (in fatigue, gadolinium-enhancing lesions on magnetic resonance imaging (MRI), and patients vs controls); and concurrent validity by correlating with disability measures.
Results:
Reliability was moderate in two (ICC = 0.601 and 0.742) and good to excellent in the remaining six features (ICC = 0.760–0.965). Patients had significantly higher keystroke latencies than controls. Latency between key presses correlated the highest with Expanded Disability Status Scale (r = 0.407) and latency between key releases with Nine-Hole Peg Test and Symbol Digit Modalities Test (ρ = 0.503 and r = −0.553, respectively), ps < 0.001.
Conclusion:
Keystroke dynamics were reliable, distinguished patients and controls, and were associated with clinical disability measures. Consequently, keystroke dynamics are a promising valid surrogate marker for clinical disability in MS
Inference and reconstruction of the heimdallarchaeial ancestry of eukaryotes
In the ongoing debates about eukaryogenesis—the series of evolutionary events leading to the emergence of the eukaryotic cell from prokaryotic ancestors— members of the Asgard archaea play a key part as the closest archaeal relatives of eukaryotes1. However, the nature and phylogenetic identity of the last common ancestor of Asgard archaea and eukaryotes remain unresolved2–4. Here we analyse distinct phylogenetic marker datasets of an expanded genomic sampling of Asgard archaea and evaluate competing evolutionary scenarios using state-of-the-art phylogenomic approaches. We find that eukaryotes are placed, with high confidence, as a well-nested clade within Asgard archaea and as a sister lineage to Hodarchaeales, a newly proposed order within Heimdallarchaeia. Using sophisticated gene tree and species tree reconciliation approaches, we show that analogous to the evolution of eukaryotic genomes, genome evolution in Asgard archaea involved significantly more gene duplication and fewer gene loss events compared with other archaea. Finally, we infer that the last common ancestor of Asgard archaea was probably a thermophilic chemolithotroph and that the lineage from which eukaryotes evolved adapted to mesophilic conditions and acquired the genetic potential to support a heterotrophic lifestyle. Our work provides key insights into the prokaryote-to-eukaryote transition and a platform for better understanding the emergence of cellular complexity in eukaryotic cells
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