237 research outputs found

    Assessment of genotype x environment interaction and stability of sesame (Sesamum indicum L.) seed yield under rainfed and supplementary irrigation in central Sudan

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    ABSTRACT       Sesame knowledge of genotype x environment interaction (GEI) is advantageous in order to have a cultivar that gives consistently high yield in a broad range of environments and to increase the efficiency of breeding programs and selection of the best genotypes. Fifteen genotypes of sesame (Sesamum  indicum L.) were evaluated during 2011 and 2012 rainy seasons, at Wad Medani, Rahad (under supplementary irrigation) and Gedarif (under rainfed), to assess genotype x environment interaction and stability of seed yield. A randomized complete block design with four replicates was used in each location. The analysis of variance procedure revealed highly significant differences among the 15 sesame genotypes for seed yield over the eight environments. The mean squares of environment, genotype and genotype x environment interaction were highly significant for seed yield. Both statistical stability models, i. e. Eberhart and Russell (1966) as well as the Additive Main Effect and Multiplicative Interaction (AMMI) analysis, indicated that genotypes Elgezouli, Promo, Um Shagra and Kenana-2 were the most high yielding and stable genotypes and can be recommended for both rainfed and irrigated areas of central Sudan.                من ميزات دراسة التفاعل الوراثي- البيئي في محصول السمسم معرفة افضل الاصناف ذات الانتاجية العالية في مدي واسع من البيئات المختلفة مما يزيد من كفاءة برامج التربية المستعملة وانتخاب افضل الاصناف. تم تقويم 15 سلالة من السمسم في الموسمين الزراعيين 2011 و2012م في ثلاثة مواقع هي مدني، الرهد (ري تكميلي) والقضارف (ري مطري)، وذلك لتقويم التفاعل الوراثي والبيئي وثبات درجة انتاجية بذور السمسم. استخدم تصميم القطاعات العشوائية الكاملة بأربع مكررات. اظهرت نتائج تحليل التباين لعدد 15 سلالة من السمسم فروقات معنوية عالية جدا لمعظم الصفات التي درست في كل المواقع والمواسم مع معنوية للتفاعل الوراثي والبيئي لإنتاجية البذور. بناءاً علي نماذج التحليل Eberhart and Russel (1966)              وAdditive Main Effect and Multiplicative Interaction(AMMI) لتحديد ثبات الاداء معاً وجد ان انتاجية بذور الاصناف الجزولي، برومو، ام شجرة وكنانة-2 ثابتة وعالية في كل المواقع والمواسم. وبناءاً علي ذلك يوصي بزراعة هذه الاصناف في المناطق المطرية والمروية في وسط السودان.                   &nbsp

    Enhancement of Bioremediation and Phytoremediation Using Electrokinetics

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    This chapter discusses the use of bioremediation and phytoremediation coupled with electrokinetics and presents the elements contributing to the success of the remediation process. A deep discussion and an overview of the current advancement in the biotechnologies are outlined in details. Innovative solutions for challenges facing the field application of the new technology are presented and new directions are proposed. A careful review for contaminated site conditions including pH, temperature, and other factors influencing the behavior of microbial community are presented. Great deal of discussion is around overcoming the adverse effect of electrolysis reactions, which is a by-product of electrokinetics. The discussion includes prolonging the survival of the indigenous bacteria, increase of microbial enzyme secretion, improvement of the indigenous bacteria metabolism, and exploration of metagenomics resources from soil biota. The challenges facing the field application of bioremediation and phytoremediation including the delivery of the electron donors and/or acceptors and nutrients to microorganisms involved in the biodegradation, particularly in clay soils, which has very low hydraulic conductivity, is discussed. The use of electrokinetics in biostimulation application to enhanced degradation of organic pollutant is reviewed. The implementation of bioaugmentation in bioremediation coupled with electrokinetics to enhance the outcome of bioremediation is presented

    Resource allocation and block coding within a three-stage collaborative broadband relay network

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    In this work we propose a power control algorithm for a multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) multi-hop collaborative relaying network. Using orthogonal and quasi-orthogonal block codes with three stage processing our algorithm optimally distributes available transmission power based on the architecture and the channel condition at each stage so as to minimize the end-to-end bit error rate (HER) of the entire relay network. For high data rate applications with maximum throughput (as expected for future OFDM systems), we employ a regenerative relaying process, where the relays at each stage decode and through collaborative processing, re-encode the received data before onward transmission to the next stage and then to the destination. We provide simulation results 1 that confirm the performance improvement in the end-to-end bit error rate (HER) of the network using our explicit power allocation algorithm as compared with equal power distribution technique

    Adaptive resource allocation within three-stage OFDM relay networks

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    In this work we consider OFDM transmission, due to its potential for meeting the stringent quality of service (QoS) targets of next-generation broadband distributed wireless networks, over three-stage relay networks. In particular, we examine distributed adaptive space-frequency coding for generally asynchronous links composed of four transmit and/or receive antennas, i.e. exploiting quasi-orthogonal and extended-orthogonal coding schemes. The successful deployment of these closed-loop methods is dependent upon channel state information (CSI) being available for each stage of the network. Taking the maximum end-to-end data rate as the optimal criterion, an adaptive resource allocation (RA) scheme suitable for a wide range of signal-to-noise-ratios (SNRs) and a prescribed transmit power budget is proposed to distribute appropriate resources to each stage based on the channel state information (CSI) and knowledge of the network topology

    An Enhanced Feedback Scheme for Extended Orthogonal Space-Frequency Block Coded MISO-OFDM Systems

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    A simple extended orthogonal space-frequency coded multiple input single output (MISO) orthogonal frequency division multiplexing (OFDM) transmitter diversity technique for wireless communications over frequency selective fading channels is presented. The proposed technique utilizes OFDM to transform frequency selective fading channels into multiple flat fading sub-channels on which space-frequency coding is applied. A four-branch transmitter diversity system is implemented without bandwidth expansion and with only one receive antenna. The associated simulations verify that the four-branch transmitter diversity scheme achieves a significant improvement in average bit-error rate (BER) performance. The proposed scheme also outperforms the previously reported scheme due to Yu et. al. with only single phase feedback, and that improvement is retained with quantized feedback. Since the angle feedback is on a per tone basis, the feedback information would be too large for any practical OFDM system. However, we adopt a method which exploits the correlation among the feedback terms for the subcarriers, i.e. a group based quantization technique to reduce the feedback overhead significantly, rendering this scheme attractive to broadband wireless access systems

    A two-hop amplify-and-forward scheme for extended orthogonal space time coding in cooperative networks

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    We investigate and propose a new amplify-and- forward cooperative relay networks scheme in which a full-rate and full-diversity extended- orthogonal space-time block coding (EOSTBC) scheme is used. Utilizing a feedback channel, a simple phase rotation is applied at the relay nodes to extract full diversity and array gain. A feedback quantization approach which reduces the overhead in the feedback channel for prac- tical systems is also proposed. The performance of the proposed scheme, with and without opti- mum power allocation strategy, is investigated. Average bit error rate simulations confirm the utility of the scheme. The results also confirm the improvement in bit error rate (BER) perfor- mance over quasi-orthogonal space time block codes (QOSTBC)

    Closed-loop extended orthogonal space frequency block coding techniques for OFDM based broadband wireless access systems

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    A simple extended orthogonal space-frequency coded multiple input single output (MISO) orthogonal frequency division multiplexing (OFDM) transmitter diversity technique for wireless communications over frequency selective fading channels is presented. The proposed technique utilizes OFDM to transform frequency selective fading channels into multiple flat fading sub-channels on which space-frequency coding is applied. A four-branch transmitter diversity system is implemented without bandwidth expansion and with only one receive antenna. The associated simulations verify that the four-branch transmitter diversity scheme achieves a significant improvement in average bit-error rate (BER) performance. The proposed scheme also outperforms the previously reported scheme due to Yu, Keroueden, and Yuan with only single phase feedback, and that improvement is retained with quantized feedback. Since the angle feedback is on a per tone basis, the feedback information would be too large for any practical OFDM system. However, we adopt a method which exploits the correlation among the feedback terms for the subcarriers, i.e. a group based quantization technique to reduce the feedback overhead significantly, rendering this scheme attractive to broadband wireless access systems. The performance improvement of convolutionally concatenated space-frequency block coding (CCSBC) schemes is also investigated

    Exploitation of quasi-orthogonal space time block codes in virtual antenna arrays: part II Monte Carlo-based throughput evaluation

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    A full rate and full diversity closed-loop quasi-orthogonal space time block coding scheme due to Toker, Lambotharan and Chambers is proposed for application in virtual antenna arrays. The performance gain is achieved through closed-loop operation involving feedback of phase rotation angle(s) calculated from channel state information (CSI) to the transmitter array. Throughput performance of the proposed scheme, with and without power optimisation, is investigated through Monte Carlo simulation with QPSK constellation signals. The results confirm the improvement in throughput performance over orthogonal space time block codes

    Effects of different levels of sugar beet roots based concentrates on the performance of Tagger male kids

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        High meat demand in the Sudan enhanced improvement of goat meat production. Tagger is a promising meat breed due to good conformation and high meat quality. Nutrition is a main constraint for goat meat production. Sugar beet is introduced into the Gezira State with no information on effects of dried sugar beet roots (DSBR) based concentrates level on Tagger kids performance, carcass characteristics and meat composition. Twelve Tagger males of 6 months old were housed in individual pens, divided into 3 groups, each with 4 animals and allocated at random to the experimental diets. They were weighed weekly for 8 weeks with a two weeks preliminary period. They were fed groundnut haulm (GNH) ad lib. in two equal meals at 8.0 am and 4.0 pm and refusals were collected and weighed daily. The animals were fed different levels of DSBR based concentrates: 0 (control), 150g and 300g, in two equal parts before GNH meals. The concentrates contained 68% DSBR,15% groundnut cakes, 15% sunflower cakes, 1% salt and 1% oyster shell. Samples of feeds and refusals were stored for laboratory analysis.  Resultd showed that groundnut haulm (30% CP, 8.8% CF, 4.8% ash and 48.2% NFE) had better proximate analysis than refusals which generally improved with concentrates levels. Dried sugar beet had 12.9% CP, 11.0% CF and 59.25% NFE and the concentrates had 42.25% CP, 2.0% CF and 49.5% NFE. Overall mean BW generally increased with concentrates level (10.78, 10.9 and 12.19kg at 0, 150 and 300g, respectively), but  not significantly different. Overall mean daily feed intakes varied with concentrates level and were 1550.89, 1187.46 and 1545.67g at 0, 150 and 300g concentrates, respectively, and were significantly least in animals fed 150g concentrates. Weekly weight gain generally increased with concentrates level in all weeks and was highest in animals fed 150g concentrates with no significant effects for concentrates level. It was 0.55, 0.68 and 0.60 kg at 0, 150 and 300g concentrates, respectively. It is recommended to use DSBR based concentrates in fattening Tagger kids.     حفز ارتفاع الطلب  على اللحوم وأسعارها في السودان تحسين لحوم الماعز. تعتبر التقر سلالة واعدة لإنتاج اللحوم لجودة القوام ونوعية اللحم.  إلا أن التغذية من المعوقات الرئيسة لإنتاج لحوم الماعز.  أدخل بنجر السكر لولاية الجزيرة ولا تتوفر معلومات عن أثر مستوى جذر البنجر الجاف) ج ب ج (على أداء جديان التقر وصفات الذبيحة  وتركيب اللحم.  وضعت 12 من ذكور جديان التقر بعمر 6 أشهر في حظائر فردية  وقسمت الى 3 مجموعات بكل منها 4 حيوانات  ووزعت عشوائيا على أعلاف الدراسة. وزنت الحيوانات أسبوعيا لمدة 8 أسابيع منها أسبوعين فترة إعدادية. أعلفت الحيوانات تبن الفول السوداني )ت ف س) حسب الرغبة في وجبتين متساويتين عند الثامنة صباحا والرابعة مساء وجمع ووزن العلف المتبقي.  كما أعلفت الحيوانات مستويات مختلفة من عليقة مركزة ترتكز على )ج ب ج  (عند صفر( الشاهد), 150 و300جم في جزئين متساويين  قبل وجبتي ت ف س. احتوت العليقة المركزة على 68% ج ب ج و15%  امباز فول سوداني و15%  تبن زهرة الشمس و1% ملح و 1% صدف  حفظت عينات من  الأعلاف والعلف المتبقي للتحليل المعملي.  حُللت المعلومات إحصائيا باستخدام تحليل التباين واستخدم اختبار دنكن لفصل اختلافات المتوسطات. كان  ت ف س (  30% بروتين خام ، 8.85 ألياف خام، 4.8% رماد و 48.2% جزء خالي من النتروجين) أحسن في التحليل التقريبي من المتبق.والذي تحسنت نوعيته بارتفاع مستوى العليقة المركزة. كان تركيب  ج ب ج 12.95 % بروتين خام ، 11% الياف خام و 59.25% جزء خالي من النتروجين .وتركيب العليقة المركزة  42.25 % بروتين خام ، 2% ألياف خام و 49.5% جزء خالي من النتروجين .  زاد متوسط الوزن الكلى مع زيادة العليقة المركزة (10.78 ،  10.9 و 12.19عند صفر و 150 و 300 جم عليقة مركزة على التوالي بدون فروقات معنوية . (P>.05)  تباين متوسط المتناول من العلف تبعاً لمستوي المركزات وكان 1550.89 و 1187.46 و 1545.67 جم عند صفر و 150 و300 جم عليقة مركزة ، علي التوالي وكان أقل معنوياً للحيوانات التي غُذيت علي  150عليقة مركزة.  تباينت زيادة الوزن الأسبوعي بزيادة مستوي العليقة المركزة في كل الأسابيع وكانت الأعلى للحيوانات عند 150 جم بدون زيادة معنوية. وكانت 0.55 و0.68 و 0.60 كجم عند صفر و 150 و300 جم عليقة مركزة، علي التوالي. يوصي باستخدام علائق جذور بنجر السكر المجففة لتسمين جديان التقر

    Generating libraries of iTol2-end insertions at BAC ends using loxP and lox511 Tn10 transposons

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    <p>Abstract</p> <p>Background</p> <p>Bacterial Artificial Chromosomes (BACs) have been widely used as transgenes in vertebrate model systems such as mice and zebrafish, for a variety of studies. BAC transgenesis has been a powerful tool to study the function of the genome, and gene regulation by distal <it>cis-</it>regulatory elements. Recently, BAC transgenesis in both mice and zebrafish was further facilitated by development of the transposon-mediated method using the Tol2 element. Tol2 ends, in the inverted orientation and flanking a 1 kb spacer DNA (iTol2), were introduced into the BAC DNA within the bacterial host using recombination of homologous sequences. Here we describe experiments designed to determine if a simpler and more flexible system could modify BACs so that they would be suitable for transgenesis into zebrafish or mouse embryos using the Tol2 transposase.</p> <p>Results</p> <p>A new technique was developed to introduce recognition sequences for the Tol2 transposase into BACs in <it>E. coli </it>using the Tn10 transposon vector system. We constructed pTnloxP-iTol2kan and pTnlox511-iTol2kan to introduce the loxP or lox511 site and iTol2 cassette, containing the Tol2 cis-sequences in the inverted orientation, into BACs that have loxP and lox511 sites flanking genomic DNA inserts by Tn10-mediated transposition. The procedure enables rapid generation of a large collection of BACs ready for transgenesis with the iTol2 cassette at the new end of a progressively truncated genomic insert via lox-Cre recombination. The iTol2 ends are efficiently recognized by the Tol2 transposase, and the BACs readily integrate into zebrafish chromosomes.</p> <p>Conclusion</p> <p>The new technology described here can rapidly introduce iTol2 ends at a BAC end of choice, and simultaneously generate a large collection of BACs with progressive deletions of the genomic DNA from that end in a single experiment. This procedure should be applicable to a wider variety of BACs containing lox sites flanking the genomic DNA insert, including those with sequence repeats. The libraries of iTol2 inserted BACs with truncations from an end should facilitate studies on the impact of distal <it>cis</it>-regulatory sequences on gene function, as well as standard BAC transgenesis with precisely trimmed genes in zebrafish or mouse embryos using Tol2 transposition.</p
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