Arboreal twig-nesting ants form dominance hierarchies over nesting resources.

Interspecific dominance hierarchies have been widely reported across animal systems. High-ranking species are expected to monopolize more resources than low-ranking species via resource monopolization. In some ant species, dominance hierarchies have been used to explain species coexistence and community structure. However, it remains unclear whether or in what contexts dominance hierarchies occur in tropical ant communities. This study seeks to examine whether arboreal twig-nesting ants competing for nesting resources in a Mexican coffee agricultural ecosystem are arranged in a linear dominance hierarchy. We described the dominance relationships among 10 species of ants and measured the uncertainty and steepness of the inferred dominance hierarchy. We also assessed the orderliness of the hierarchy by considering species interactions at the network level. Based on the randomized Elo-rating method, we found that the twig-nesting ant species Myrmelachista mexicana ranked highest in the ranking, while Pseudomyrmex ejectus was ranked as the lowest in the hierarchy. Our results show that the hierarchy was intermediate in its steepness, suggesting that the probability of higher ranked species winning contests against lower ranked species was fairly high. Motif analysis and significant excess of triads further revealed that the species networks were largely transitive. This study highlights that some tropical arboreal ant communities organize into dominance hierarchies

Promoting adoption of improved seed through the Direct Seed Marketing approach

Poster prepared for a share fair, Addis Ababa, May 201

Genetic variability of vancomycin-resistant Enterococcus faecium and Enterococcus faecalis isolates from humans, chickens and pigs in Malaysia

Vancomycin-resistant enterococci (VRE) have been reported to be present in humans, chickens, and pigs in Malaysia. In the present study, representative samples of VRE isolated from these populations were examined for similarities and differences by using the multilocus sequence typing (MLST) method. Housekeeping genes of Enterococcus faecium (n = 14) and Enterococcus faecalis (n = 11) isolates were sequenced and analyzed using the MLST databases eBURST and goeBURST. We found five sequence types (STs) of E. faecium and six STs of E. faecalis existing in Malaysia. Enterococcus faecium isolates belonging to ST203, ST17, ST55, ST79, and ST29 were identified, and E. faecium ST203 was the most common among humans. The MLST profiles of E. faecium from humans in this study were similar to the globally reported nosocomial-related strain lineage belonging to clonal complex 17 (CC17). Isolates from chickens and pigs have few similarities to those from humans, except for one isolate from a chicken, which was identified as ST203. E. faecalis isolates were more diverse and were identified as ST4, ST6, ST87, ST108, ST274, and ST244, which were grouped as specific to the three hosts. E. faecalis, belonging to the high-risk CC2 and CC87, were detected among isolates from humans. In conclusion, even though one isolate from a chicken was found clonal to that of humans, the MLST analysis of E. faecium and E. faecalis supports the findings of others who suggest VRE to be predominantly host specific and that clinically important strains are found mainly among humans. The infrequent detection of a human VRE clone in a chicken may in fact suggest a reverse transmission of VRE from humans to animals

Species distribution and resistance phenotypes of vancomycin-resistant enterococcus isolated from pigs in Pulau Pinang, Malaysia

Vancomycin-resistant enterococci (VRE) are important nosocomial pathogens. The extensive use of avoparcin as a growth promoter in poultry and pigs is the hypothesized factor for the emergence of vancomycin resistance in enterococci in animals. As pork is one of the major protein sources for 30% of Malaysians, the present study was conducted to elucidate the role of pigs in the epidemiology of VRE. In this study, 220 rectal swabs were collected from pigs at 12 pig farms in Pulau Pinang. The study found 10 of 12 farms (83.3%) and 92 (41.8%) of the sampled pigs were positive for VRE. Of the 92 isolates examined by PCR, E. faecium (14%), E. casseliflavus (21.7%), E. gallinarum (1.1%) and other Enterococcus species (63.0%) were identified. VanA was detected in E. faecium and E. gallinarum. Questionnaire survey indicated that none of the sampled farms had used glycopeptides, either for growth promotion or for therapy. Tylosin, which has also been associated with vancomycin cross-resistance, was used in 41.8% of the sampled farms; however, there was no significant difference (P>0.05) between the proportion of VRE detected in the farms which used tylosin to those farms which did not. E-test on selected 49 isolates showed 16.0% of the isolates had MIC≤8 and 22.0% had MIC≥32. Single isolates of E. faecium and E. gallinarum, both possessed the resistance gene vanA, showed very high resistance (MIC>256). About 10.0% of the isolates, in which van genes was not detected, had MIC>32. In conclusion E. faecium and E. faecalis were found to be present at a low rate in the pigs sampled in this study. However, detection of vanA with high level of vancomycin resistance (MIC>256) highlights the potential public health threat associated with the pigs

Exploring the Relationship between Spectators’ Experience with Sportscape Elements and Propensity to Re-Patronize: Evidence from Addis Ababa Stadium, Ethiopia

The purpose of this study was to explore the relationship between spectators’ experience with sportscape elements and propensity to re-patronize in Addis Ababa stadium, Ethiopia. The survey instrument was administered to 150 spectators’ from all seating sections at four different games based on the sportscape model proposed by Wakefield, Blodgett and Sloan (1996) and  Theodorakis and Alexandris (2008) SPORTSERV model. Based on descriptive analysis, spectators’ appeared to have unpleasant experience with majority of the studied sportscape elements and despite the unfavorable experience; result of the regression analysis depicts none significant relationship with spectators’ propensity to re-patronize or attend future games in the stadium. Keywords: Spectators’ Experience, Sportscape Elements, Propensity to Re-Patronize

Short-run Behavior of Defensive Assets in the Ethiopian Commercial Banking Sector

The paper aims to identify and measure the impact of factors responsible in shaping the behavior of defensive assets in the Ethiopian banking sector. The focus of the analysis is on the Ethiopian banking sector rather than an individual bank. An attempt is made to capture how the Ethiopian banking sector adjusts its defensive asset position to changes in money supply, relative yields on asset holdings, discount rate, the demand for different bank assets, availability of funds, and legal reserve requirements. Except for required reserves, discount rate and relative yields on asset holdings, the rest of the explanatory variables are statistically significant in explaining the short-run behavior of defensive assets. The paper concludes initial stock of excess reserves, treasury bills, loans and their lag, narrow money supply, saving deposit of the public held with different financial institutions, and bank capital are what explain short-run behavior of defensive assets in the Ethiopian banking sector. Finally, the difference in the behavior of excess & free reserves found to be negligible which is a signal of insignificant use of short-term borrowings in the Ethiopian commercial banking system

Determinants of Loan Repayment: Evidence from Group Owned Micro and Small Enterprises, Tigray, Northern Ethiopia

The study aims to investigate factors affecting loan repayment performance of the group owned MSEs taking borrower characteristics in to consideration. The primary data was collected by distributing semi-structured questionnaire and interviewing 62 group owned MSEs located in Mekelle city, Tigray Regional state of Ethiopia financed by DECSI by using census method, of which 13 group owned MSEs were found to be defaulters and the remaining, 49 MSEs were non-defaulters. An econometrics model (Binary Logistic Regression) was used to analyze the effect of the literature driven variables have on loan repayment (dependent variable). The binary logistic regression result shows among the variables hypothesized to affect loan repayment, initiation and sector have statistically significant effect on loan repayment. Whereas like group composition and group size have statistically insignificant effect on loan repayment.  Therefore, to improve the loan repayment performance of the group owned MSEs and increase the potential contribution of MSEs to the economic growth of the country, all concerned stakeholders must to play their role. Keywords: Determinant, Loan Repayment, Group Owned, Micro and Small Enterprises, Binary Logistic Regression Logistic, Tigray, Ethiopia

Population Level Consequences of Spatial Networks: Species Coexistence and Implications for Invasive Species

In Chapter I, I developed a network model of inter-specific competition that generated two distinct spatial patterns: mosaics and spiral waves. We find that diversity is rapidly lost when dispersal and interactions occurs over relatively small spatial scales (i.e. small amounts mixing). This pattern of diversity loss is more pronounced under negative and zero covariance levels, while species diversity is maintained under a positive covariance. In Chapter II, I investigated the ecological differences in resource discovery and recruitment by W. auropunctata within its native range (Mexico) and introduced range (Puerto Rico). We found that W. auropunctata was slower at discovering resources in Puerto Rico, as compared to its native range of Mexico. This suggests that competitive traits such as resource discovery and recruitment are not necessarily indicative of invasive success. In Chapter III, I investigated the invasion dynamics of the little fire ant Wasmannia auropunctata. Our results provide support for the biotic-resistance hypothesis in which native ant species in Mexico are able to resist W. auropunctata as compared to the introduced range of Puerto Rico. However, this pattern depends strongly on the temporal aspect of invasion. We propose that temporal considerations are necessary when determining the competitive abilities of native and exotic ants. In Chapter IV, I examined the effects of phorid flies on the competitive outcome between the arboreal ants W. auropunctata and native ant L. iniquum. We found that the presence of phorid fly significantly reduced recruitment of L. iniquum workers to resources through induced behavioral changes thereby increasing the invasion ability of W. auropunctata. In Chapter V, I examined competitive networks among twig nesting ant species at local and regional spatial scales across a 50-ha coffee farm. We found that dominance rank of ant species was not correlated with relative abundance across the entire coffee farm; however, transitive networks were correlated with increases in relative abundance at the local scale compared with relative abundances at the regional scalePHDEcology and Evolutionary BiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/135785/1/senay_1.pd

A Problem of Social Capital and Cultural Norms?

This paper asserts that in Ethiopian society, there exist certain cultural norms or ‘dysfunctional behaviours’ that inhibit effective communication, lead to intra-group conflict, and make conflict resolution difficult. This has resulted in a diminished capacity for cooperation and a dearth of social capital and civil society, which does not bode well for development and democracy. It is imperative that research is expanded in the neglected area of cultural norms and social capital in Ethiopian society, and that intervention strategies are designed to increase social capital by addressing cultural norms directly through social marketing, awareness raising, and other mechanisms