Socioeconomic and Environmental Assessment of Woody Biofuels in Southern United States

Although the emergence of woody bioenergy offers several energy, economic, social, and environmental benefits, forestland owners’ willingness to participate in a biomass supply market, how it affects land use choices, and forestland owners’ sustainability concerns are not well understood. In addition to these gaps, how much residual biomass forestland owners are willing to retain on site for soil fertility and other environmental benefit purposes and forestland owners’ tendency to enroll in public incentive programs are not fully documented. Because private forestland owners manage two thirds of the 214 million acres of forest cover in the southern United States, understanding their response to a growing woody biofuels industry is important, among others towards assessing its sustainability. This dissertation addresses these issues using primary data collected from the southern states of Virginia and Texas, which are among the most resource rich states where private forestland owners play a significant ownership role

Forest Carbon Stocks in Woody Plants of Arba Minch Ground Water Forest and its Variations along Environmental Gradients

The role of forests in mitigating the effect of climate change depends on the carbon sequestration potential and management. This study was conducted to estimate the carbon stock and its variation along environmental gradients in Arba Minch Ground Water Forest. The data was collected from the field by measuring plants with a DBH of >5cm in quadrat plots of 10 X 20 m and the carbon stocks of each plant were analyzed by using allometric equations. From this study the mean total carbon stock density of Arba Minch Ground Water Forest was found to be 583.27 t ha-1, of which 829.12 t ha-1, 165.88 t ha-1, 1.28 t ha-1, 83.80 t ha-1 was contained in the above ground carbon, belowground carbon, litter carbon and soil organic carbon (0-30 cm depth) 0respectively. Similarly, the analysis of carbon stock variation of different carbon pools on eight different aspects of the forest area showed a significant variation with the exception of litter carbon stock and this is due to fast decomposition rate of litters and low amount of litter fall in the forest. The amount of carbon stock in above and belowground biomass, soil organic carbon and the total carbon stock was higher on the southern aspect as compared to other aspects. This study concluded that the carbon stock value of Arba Minch Ground Water Forest is large, and this will serve as a potential entry point for the engagement of the forest in REDD project.Keywords: Environmental variables; Ground Water Forest; Climate change; Biomass; Forest carbon stoc

When it Pays to Rush: Interpreting Morphogen Gradients Prior to Steady-State

During development, morphogen gradients precisely determine the position of gene expression boundaries despite the inevitable presence of fluctuations. Recent experiments suggest that some morphogen gradients may be interpreted prior to reaching steady-state. Theoretical work has predicted that such systems will be more robust to embryo-to-embryo fluctuations. By analysing two experimentally motivated models of morphogen gradient formation, we investigate the positional precision of gene expression boundaries determined by pre-steady-state morphogen gradients in the presence of embryo-to-embryo fluctuations, internal biochemical noise and variations in the timing of morphogen measurement. Morphogens that are direct transcription factors are found to be particularly sensitive to internal noise when interpreted prior to steady-state, disadvantaging early measurement, even in the presence of large embryo-to-embryo fluctuations. Morphogens interpreted by cell-surface receptors can be measured prior to steady-state without significant decrease in positional precision provided fluctuations in the timing of measurement are small. Applying our results to experiment, we predict that Bicoid, a transcription factor morphogen in Drosophila, is unlikely to be interpreted prior to reaching steady-state. We also predict that Activin in Xenopus and Nodal in zebrafish, morphogens interpreted by cell-surface receptors, can be decoded in pre-steady-state.Comment: 18 pages, 3 figure

Sampling rare switching events in biochemical networks

Bistable biochemical switches are ubiquitous in gene regulatory networks and signal transduction pathways. Their switching dynamics, however, are difficult to study directly in experiments or conventional computer simulations, because switching events are rapid, yet infrequent. We present a simulation technique that makes it possible to predict the rate and mechanism of flipping of biochemical switches. The method uses a series of interfaces in phase space between the two stable steady states of the switch to generate transition trajectories in a ratchet-like manner. We demonstrate its use by calculating the spontaneous flipping rate of a symmetric model of a genetic switch consisting of two mutually repressing genes. The rate constant can be obtained orders of magnitude more efficiently than using brute-force simulations. For this model switch, we show that the switching mechanism, and consequently the switching rate, depends crucially on whether the binding of one regulatory protein to the DNA excludes the binding of the other one. Our technique could also be used to study rare events and non-equilibrium processes in soft condensed matter systems.Comment: 9 pages, 6 figures, last page contains supplementary informatio

Determinants of Inflationary Experience in Ethiopia

The main aim of this study is to investigate the determinants of inflationary experience in Ethiopia. The study focused on economic and econometric criterion to examine the long run and short run impacts of macroeconomic variables on inflation in Ethiopia. In order to accomplish this paper, the study has employed time series data for the period from 1974/75 to 2014/15. To check for the stationarity of the variables, the researcher has used augmented dickey fuller and Phillips-Perron unit root test and all variables become stationary at first difference. Then, long run and short run estimates had been examined by using Johansen Co-integration methodology and Vector Error Correction approach with lag length of two. The data on macroeconomic variables were taken from National Bank of Ethiopia, Ethiopian Economic Association and World Bank database. The findings of the study indicated that in the long run consumer price index has found to be positively influenced by money supply, real gross domestic product and overall budget deficit in which these all variables are positive and statistically significant determinants of inflation. The growth of money supply should be continually kept in control, given its long run potential impact in accelerating inflationary pressure to ensure stable price level in an economy and keep on the growth of real gross domestic product with single digit inflation rate and displaying a high sense of transparency in fiscal operations bring about a realistic budget deficit that would serve as incentives to productivity and stable general price level

Mega-Environment Targeting of Maize Varieties using Ammi and GGE Bi-Plot Analysis in Ethiopia

አህፅሮት በቆሎ በኢትዮጵያ  ከሚመረቱ የምግብ ሰብሎች መካከል በምርትና ምርታማነቱ ግንባር ቀደም ስፍራን የያዘ ሰብል ነው፡፡  የሰብሉን ምርታማነት ከሚደግፉ የተለያዩ መንስዔዎች  ውስጥ በዋናነት ከፍተኛውን  ቦታ  የሚይዙት ከጥናትና ምርምር  የተገኙ የተሻሻሉ ዝርያዎች ቢሆኑም ሁሉም ዝርያዎች   በበቆሎ አብቃይ ስነ-ምህዳሮች  ላይ ተዘርተው  በምርታማነታቸው ወጥነት የማያሳዩ መሆናቸው ይታወቃል፡፡ እንደየአካባቢው የአይር ፀባይ፤ የአፈር ዓይነትና የዝናብ መጠን እንዲሁም የመሬት ከባህር ወለል ከፍታ ልዩነት የተነሳ በምርታማነታቸው ለየአካባቢው ተመራጭና ተመራጭ ያልሆኑ ዝርያዎችን መለየት ይቻላል፡፡ በዚህ ምክንያት ለተለያዩ ዝርያዎች ምርታማነት ተስማሚና ወካይ የሆኑ ስፍራዎችን  ለይቶ በማወቅ የትኛው ዝርያ በየትኛው ስፍራ ላይ ቢዘራ  ሁለንተናዊ የአካባቢ ባህሪያትን  ተላብሶ ከፍተኛ ምርት ሊሰጥ ይችላል?  እንዲሁም የትኛቹ ስፍራዎች በአየር ንብረት ተቀራራቢነት በጥቅል ተደምረው አንድ ዝርያ በወጥነት  በሁሉም ስፍራ ተዘርቶ ምርታማ የሚያደርጋቸውን አካባቢዎች ለይቶ ለማወቅ ጥናቱ ተደረገ፡፡ ጥናቱ ለምርት በምርምር የተለቀቁ  19 ዲቃላ የበቆሎ ዝርያዎችን በማካተት  ወይናደጋማና ደጋማ ስፍራዎች ላይ ተዘርተው የተለያዩ መረጃዎችን  በማሰባሰብ እንዲጠናቀር ከተደረገ በኋላ ለጥናቱ ስኬት   ከፍተኛ ትኩረት ተሰጥቶት  ለውሳኔ  እንዲያመች ከየአካባቢው የተሰበሰቡ የዝርያዎቹ ምርት አግባብ ባላቸው ሳይንሳዊ ዘዴዎች እንዲሰሉ ተደረገ፡፡ በስሌቱ መሰረት ከዝርያዎቹ በአማካይ በሔክታር 4.47 ( BH545)  እስከ 7.49  ( BH546) ቶን  ምርት ተመዘገበ፡፡ እንዲሁም በተደረገው ስሌት G14  እና  G1  ተብለው የተለዩ ዝርያዎች ለአብዛኞቹ የጥናቱ ስፍራዎች ተስማሚ  እንደሆኑ  ቢታወቅም  BH546  በሚባል ስያሜ የሚለየው ዝርያ በከፍተኛ ደረጃ ተመራጭ እንደሆነ ለማረጋገጥ ተችለሏል፡፡ በሌላ በኩል E9  በተባለ ምህፃረ-ቃል የሚለይ ስፍራ በአብዛኛው ዝርያዎች  ተመራጭ እንደሆነ ስሌቱ ሲያሳይ ፤ E1  የተባለው ግን ተመራጭ እንዳልሆነ ታውቋል፡፡ ሆኖም ግን 11 የጥናት ስፍራዎች በሶስት ዋና ዋና ፤ እያንዳንዳቸው በዝርዎቹ ምርታማነት የጎላ ልዩነት በሚታይባቸው ወጥ ክፍሎች እንደተከፈሉ የስሌቱ ውጤት ለይቶ አሳይቷል፡፡ በዚህ መሰረት E9 በሚል ስያሜ የሚለየው ስፍራ በብቸኝንት እንደ አንድ ዋና ክፍል የተከፈለ ሲሆን በሁለተኛ  ክፍል ውስጥ  በጥቅል  ዘጠኝ  አካባቦዎች  E1, E2, E3, E5, E6, E7, E8  እና E11  በአንድነት ተደመሩ፤ እንዲሁም  E4 እና  E10 በሶስተኛው ክፍል ውስጥ ተመደቡ፡፡ E3, E5 and, E7 በተባሉ ምህፃረ-ቃል የተለዩ ስፍራዎች ለዝርዎቹ ምርታማነት ወካይና ተመራጭ መሆናቸውን ጥናቱ አሳየ፡፡  ነገር ግን E4, E9 and E10  የተባሉ አካባቢዎች በውስን ስፍራዎች ውስጥ  ምርታማ የሚሆኑ  ዝርያዎችን መለየት የሚችሉ መሆናቸውን ጥናቱ ያረጋግጣል፡፡  በሌላ በኩል E8 and E11 የተባሉ ስፍራዎች የዝርያዎችን ምርታማነትና ተመራጭነት  በጉልህ ለማሳየት ምንም አስተዋፅዖ ያላበረከቱ መሆናቸውን ጥናቱ አሳይቷል፡፡ በመጨረሻም የዚህ ጥናት ውጤት ወጥነት ያላቸው ሶስት ዋና ዋና ስነ-ምህዳራትን ለይቷል፤  ዝርይዎች በምርታማነታቸው   ተመራጭነት  የሚኖራቸውንና  የማይኖራቸውነ  ለይተው የሚያሳዩ ስፍራዎችን  ጠቁሟል እንዲሁም በምርታማነቱና ለአብዛኛው አካባቢዎች  በወጥነት ተስማሚነቱን የሜያሳይ ዝርያ ለይቶ አሳይቷል፡፡ Abstract In multi-location experimental trials, test locations must be selected to properly discriminate between varieties and to be representative of the target regions. The objective of this study were to evaluate test locations in terms of discrimination ability, representativeness, and desirability, and to investigate the presence of mega-environments using AMMI and GGE models and to suggest representative environments for breeding and variety testing purposes.  Among 19 maize varieties tested across 11 environments, mean grain yield ranged between 4.47 t/ha (BH545) to 7.49 t/ha (BH546). Both AMMI and GGE  models identified   G14 and G1 as  desirable hybrids for cultivation   because they combined stability and higher average yield. Nonetheless, as confirmed by GGE analysis BH546 was most closest to the ideal genotype hence, considered as best hybrid.  Environment wise, E9 and E4 were the most stable and unstable test environments, respectively. The 11 test environments fell into three apparent mega-environments.  E9 formed one group by its own, E1, E2, E3, E5, E6, E7, E8 and E11 formed the second group and E4 and E10 formed the third group.  E3, E5 and, E7 were both discriminating and representative therefore are favorable environments for selecting generally adapted genotypes. E4, E9 and E10 were discriminating but non-representative test environments thus are useful for selecting specifically adapted genotypes. E8 and E11 were non-discriminating test environments hence little information about the genotypes. The results of this study helped to identify mega-environments, also representativeness and discriminating power of test environments better visualized with the GGE bi-plot model