Speech-evoked ABR: Effects of age and simulated neural temporal jitter

The speech-evoked auditory brainstem response (sABR) provides a measure of encoding complex stimuli in the brainstem, and this study employed the sABR to better understand the role of neural temporal jitter in the response patterns from older adults. In experiment 1, sABR recordings were used to investigate age-related differences in periodicity encoding of the temporal envelope and fine structure components of the response to a /da/speech token. A group of younger and a group of older adults (n = 22 per group) participated. The results demonstrated reduced amplitude of the fundamental frequency and harmonic components in the spectral domain of the recorded response of the older listeners. In experiment 2, a model of neural temporal jitter was employed to simulate in a group of young adults (n = 22) the response patterns measured from older adults. A small group of older adults (n = 7) were also tested under the jitter simulation conditions. In the young adults, the results showed a systematic reduction in the response amplitude of the most robust response components as the degree of applied jitter increased. In contrast, the older adults did not demonstrate significant response reduction when tested under jitter conditions. The overall pattern of results suggests that older adults have reduced neural synchrony for encoding periodic, complex signals at the level of the brainstem, and that this reduced synchrony can be modeled by simulating neural jitter via disruption of the temporal waveform of the stimulus

Patterns of Land Use/Cover Dynamics in the Mountain Landscape of Tara Gedam and Adjacent Agro-Ecosystem, Northwest Ethiopia

This study analyzed land use/cover dynamics in the mountain landscape of Tara Gedam and adjacent agro-ecosystem of northwest Ethiopia over a period of 46 years (1957–2003). The changes were measured through interpretation of aerial photographs taken in 1957 and 1980, and Land-sat satellite image of 2003 using Arc gis 9.2 software, supported by focal group discussions and field visits. Three separate maps (for years 1957, 1980 and 2003) of the study area were produced and six major land use/cover classes were identified: dense forest, woodland, shrub land, grassland, riverine vegetation and cultivated and settlement land. The results indicated that the main land trajectory was from natural vegetation cover to settlement and cultivated land. The cultivated and settlement land coverage increased by 90.60% between 1957 and 2003. However, woodland, dense forest, riverine vegetation, shrub and grasslands coverage declined by 97.87, 71.04, 37.00, 9.02 and 3.03%, respectively. These could be mainly attributed to anthropogenic factors. Increasing demands of more land for cultivation and settlement, overgrazing, deforestation for fuel wood and construction have resulted in a dramatic shrinkage of the area under natural vegetation. The 1975 national land reform proclamation of the country had also contributed to the expansion of cultivated and settlement land. The implications of these changes are increased land degradation and loss of biodiversity affecting the livelihood of the community. It is suggested that the study area needs an immediate intervention for developing sustainable land use practices and to manage the remaining natural vegetation and to rehabilitate the degraded lands

A Comparative Study on Changes in Cardiovascular Indices of Cobblestone Workers in Addis Ababa, Ethiopia

Cobblestone projets have become good job opportunities for hundred thousands of citizens. However, workers are at risk of health problems due to physical injury and exposure to dust particles during work activities. The study was designed to determine acute and chronic changes in cardiovascular indices of cobblestone workers in Addis Ababa, Ethiopia. Comparative cross-sectional study method was applied. Cobblestone workers exposed for one and above years and proportional number of non exposed groups from Addis Ababa University summer non- smoking normal students within the same age range and sex proportion were participated. Acute exposure standard was established on an eight-hour exposure time frame. HR, %SPO2 and ABP were measured before and after a day work exposure, using pulse oxi-meter and sphygmomanometer. The study showed significant change in cardiovascular indices compared with controls. The mean value of %SPO2 was reduced significantly (p=0.03) in exposed groups compared to non exposed groups. The mean value±SD of HR in exposed groups showed very significant increment (p=0.001) and variability was reduced. Both sPB (p=0.006) and dBP (p=0.001) showed very significant increment. From this study, it could be concluded that dust emission during cobblestone work affects the cardiovascular function of cobblestone workers. Acute and chronic exposure to dust for some hours leads to very significant changes in cardiovascular indices. Regular inspection and further study is recommended together with full co-operation among the competent authority, researchers, workers and occupational health professionals.

Land, soil and water management

This chapter reviews relevant Vertisol properties, experimental results and the overall experience of the project on this subject. There are several types of drainage problems in Vertisols whose magnitude may vary from site to site. Drainage improvement is discussed in relation with camber beds, broadbeds and furrows, field depressions, perched watertable, open ditches, height of beds, soil erosion and supplemental irrigation. The need for water shed development projects is also examined

Empowerment and Tech Adoption: Introducing the Treadle Pump Triggers Farmers’ Innovation in Eastern Ethiopia

In 2013, thirty-eight treadle pumps (TPs) were installed as low-cost technology introduction for small-scale irrigation in eastern Ethiopia. This pilot project also trained six farmers on tube well excavation, as well as the installation and maintenance of pumps. In June 2015, researchers visited nine of the thirty-eight TP villages and found only two TPs functioning as originally installed. The rest were replaced with a new technology developed by the trained farmers. Farmers, empowered by training, gained more control in developing technology options tailored to local needs and conditions of their communities. Adopters of the new technology stated that the limited water output and high labor demand of the conventional TP did not optimally fulfil their irrigation water requirements. The new technology had spread quickly to more than one hundred households due to three key factors. First, farmers’ innovative modifications of the initial excavation technique addressed the discharge limitations of the conventional TP by excavating boreholes with wider diameter. Second, local ownership of the new technology, including skills used in well drilling and manufacturing excavation implements, made the modified irrigation technology affordable and accessible to the majority of households. Third, this innovation spread organically without any external support, confirming its sustainability

Are antipsychotic prescribing patterns different in older and younger adults? : a survey of 1357 psychiatric inpatients in Toronto

Objective: To compare antipsychotic prescribing patterns in younger (aged 59 years or younger) and older (aged 60 years or older) patients with psychotic or mood disorders. Method: Pharmacy records of all patients discharged from the Centre for Addiction and Mental Health over a 21-month period were reviewed. A total of 1357 patients who were prescribed an antipsychotic at the time of their discharge were included in the analysis (956 with a primary psychotic disorder and 401 with a primary mood disorder). World Health Organization-defined daily doses were used as the standardized dosing unit. Results: Both in patients with a primary psychotic disorder and in patients with a primary mood disorder, the prescribing patterns were similar in older and younger patients, with no statistical difference in the proportions receiving first-generation antipsychotics, second-generation antipsychotics (SGAs), multiple antipsychotics, or long-acting (depot) antipsychotics. Overall, the mean daily antipsychotic doses were lower only in the older group of patients with a primary mood disorder. However, the mean dose of SGAs was about 30% lower in older patients in both diagnostic groups. Regardless of age, patients with a mood disorder were prescribed lower doses of antipsychotics than those with a psychotic disorder. Conclusions: Our data suggest that older patients are prescribed lower antipsychotic dosages primarily when using SGAs. This finding emphasizes the need for dose-finding studies assessing both the efficacy and the safety of antipsychotics in older patients with a psychotic or mood disorder.peer-reviewe

Using engineering design tools in multidisciplinary distributed student teams

Collaborative design practice in distributed student teams is becoming more popular as technology makes it easier to communicate ideas with others that are geographically distant. However, a challenge for students is to use design tools which they are not familiar with. These design tools usually differ from each other and engineers may find it much more difficult to share their ideas. This could make the whole design process longer and less successful. Each year the University of Malta, City University London and University of Strathclyde organise a joint collaborative design project, involving engineering students with different disciplines and cultural backgrounds. In this paper, the patterns of use of design tools by students to collaborate with each other are investigated. Based on survey results of students, this paper proposes an approach which can be utilised by engineering students to enhance collaboration in multidisciplinary distributed design teams

Identifying and Addressing Soil Property Issues Affecting Roadside Vegetation Establishment

Attaining adequate vegetation cover along highways is important for NDOR to comply with EPA’s stormwater regulations. However, low plant cover is a common problem on shoulders (first 16 feet off the pavement) of many highways in Nebraska. The ultimate goal of this study is to identify cost-effective engineering solutions that assure adequate seed beds (i.e., soil conditions) for establishment of selected seeding mixtures. The objectives of this study are to (1) characterize the soil properties along roadsides where vegetation stands have not developed well, and (2) verify the effects of select soil property parameters on plant germination and establishment. Sampling occurred at multiple locations along the highways near Beaver Crossing and Sargent, NE. At each location, soil samples were collected from a transect of multiple landscape positions, perpendicular to the highway. The soil physical properties measured included cone index, sorptivity, and aggregate stability, while the soil chemical properties measured included EC, pH, organic matters, Na, and Ca. Results show that the soils near the edge of the highway pavement were highly compacted. Also, the soils had higher pH, lower organic matter, and higher salt levels than optimal conditions. In the subsequent greenhouse studies, a factorial design was used to test three factors: soil compaction (i.e., 1.5, 1.7, and 1.9 g cm-3 soil compaction levels as well as sand as control), timing of salt stress (2 pulses of salt treatment applied pre-germination and post-germination as well as no-salt control), and plant species (buffalo grass, tall fescue, and western wheat grass). Results from the greenhouse studies showed that the three plant species exhibited different germination and early survival responses to the soil compaction and salt treatments. Tall fescue is better suited for site re-vegetation especially if salt is present in the soil prior to germination. Statistical analysis show that salt treatment had the most impact on species performance. Finally the project recommends a few engineering remediation strategies for plant establishment. Creating microsites on compacted soil surfaces could potentially alleviate the soil compaction issue by creating local environmental conditions favorable to plant establishment at microsites. To remediate the high salt levels in soil, it is recommended to consider alternative de-icing agents and amend zeolites and organics in soil