Physical Sciences and Mathematics Commons^™

Global Impact Of Sown Temperate Pastures On Productivity And Ecosystem Stability–What Progress Have We Made?, E. Charles Brummer

IGC Proceedings (1977-2023)

Twenty years ago, in 1993, we published one of the first two alfalfa genetic linkage maps. At the time, hopes ran high that genetic marker technologies would revolutionize selection, making the development of superior cultivars both easier and faster. The objective of this paper is to critically examine forage improvement since that time and to suggest ways to more fully capitalize on those initial hopes in the future. Marker studies have been conducted around the world, identifying quantitative trait loci (QTL) for the major agronomically important traits, including biomass yield, nutritive value, disease resistance, abiotic stress tolerance, and others. But …

Structural Characteristics Of Porto Rico Stargrass (Cynodon Nlemfuensis) Pastures Under Different Frequencies And Severities Of Defoliation, Carlos Augusto Brandão De Carvalho, Sergio Trabali Camargo Filho, Domingos Sávio Campos Paciullo, Pablo Giliard Zanella, Elisa Cristina Modesto, Priscila Beligoli Fernandes

IGC Proceedings (1977-2023)

An understanding of the effects of frequency and severity of defoliation on the sward structure of pastures is essential for identifying pasture management strategies that are more efficient in forage usage in tropical environments (Da Silva and Nascimento Jr 2007; Euclides et al. 2010). Some pasture species have not yet been investigated in this way, e.g. cultivars of Cynodon. The potential of this grass in tropical environments suggests that it should be given priority (Pedreira 2010). This study was designed to evaluate the effects of 2 frequencies (90 and 95% light interception) and severities (20 and 30 cm …

Effect Of Grazing Height On Marandu Pasture Production And Performance Of Soybean Grain-Supplemented Nellore Bulls, Andre L. S. Valente, Ricardo A. Reis, Sharadinny M. C. Dos Santos, Fernando H. M. De Souza, Telma T. Berchielli, Ana C. Ruggieri, Sabrina S. Santana, Juliana M. Serra

IGC Proceedings (1977-2023)

The Brazilian beef cattle industry is primarily based on the use of pastures. Grasses belonging to the genus Brachiaria are extremely important, regardless of whether the production system used is intensive or extensive.

Appropriate management of the system is vital for obtaining a high efficiency of resource usage. Adjustment of stocking rate to maintain optimum forage allowance and feeding of supplements are strategies for achieving these aims. Feeding of concentrates on pasture can result in increased carrying capacity and higher weight gains over unsupplemented systems.

The purpose of this study was to evaluate the effects of 3 different grazing heights …

Establishment Of Leucaena Leucocephala Cv. Tarramba In Eastern Indonesia, Jacob Nulik, H. Dahlanuddin, Debora Kana Hau, Charles Pakereng, Resti G. Edison, Dessy Liubana, S. P. Ara, Hayley E. Giles

IGC Proceedings (1977-2023)

The adaptability and productive value of Leucaena leucocephala cv. Tarramba (Tarramba) in eastern Indonesia has been observed since 2001 (Nulik et al. 2004), with many farmers and other stakeholders currently requesting seed for planting. Tarramba has greater forage and timber production, and psyllid tolerance than other commercial cultivars and locally grown leucaena. The variability of soils and climate in eastern Indonesia means that establishment techniques specific to the region are required to achieve maximum adoption and utilisation of Tarramba.

Potential Of Australian Bermudagrasses (Cynodon Spp.) For Pasture In Subtropical Australia, Andrew Hacker, Meena Puachuay, H. Max Shelton, Scott A. Dalzell, Haider Al Dabbagh, Margaret Jewell, Thinh Van Tran, The Ngo, Yi Zhou, Michael J. Halliday, Hayley E. Giles, Don S. Loch, Ian D. Godwin, Fukai Shu, Chris O’Brien, Will Pearce, William F. Anderson, Christopher J. Lambrides

IGC Proceedings (1977-2023)

In Australia, little work has been carried out on the improvement of tropical or subtropical pastures in recent years. There seems to be an increasing demand for pastures that can withstand heavy grazing, while producing high yields of high quality forage in the humid subtropical regions of Australia. Most graziers, who live in these areas, have small acreages, which they graze intensively. Cynodon spp. represent a potential source of grasses with these attributes. This study will evaluate the pasture potential of a large number of bermudagrass (Cynodon spp.) ecotypes collected from across Australia.

Selection Of Psyllid-Resistant Forage Varieties From An Inter-Specific Breeding Program Of Leucaena Leucocephala With L. Pallida, Scott A. Dalzell, Lachlan M. Robertson, Christopher J. Lambrides, James L. Brewbaker, Del Greenway, Mark Dieters, H. Max Shelton

IGC Proceedings (1977-2023)

Leucaena (Leucaena leucocephala) pastures for beef cattle production are productive and sustainable; however, susceptibility to the psyllid insect (Heteropsylla cubana) has limited expansion of current commercial cultivars into more humid areas (> 800 mm/yr) (Shelton and Dalzell 2007). Psyllids can also cause intermittent damage in lower rainfall regions during humid periods. The psyllid, which arrived in Australia in 1986, is a leaf-sucking insect specific to the Leucaena genus, feeding on the growing tips of susceptible cultivars (Bray 1994). Psyllid damage can reduce production by as much as 50-70% in humid regions and 20-50% in subhumid environments …

Growth Of Bali Bulls On Rations Containing Sesbania Grandiflora In Central Lombok, Indonesia, H. Dahlanuddin, Baiq Tutik Yuliana, Tanda Panjaitan, Michael J. Halliday, H. Max Shelton

IGC Proceedings (1977-2023)

The demand for meat in Indonesia is currently growing by up to 8% per year, with beef cattle fattening identified as a major livestock industry (Purwantara et al. 2012). Bali cattle (Bos javanicus) account for almost 27% of total beef cattle in Indonesia; they are the predominant breed in the eastern islands and are highly favoured by smallholder farmers for their high fertility, low calf mortality and generally higher price at markets (Purwantara et al. 2012). Lombok in west Nusa Tenggara is one of the biggest suppliers of Bali cattle in Indonesia.

A major constraint to …

Animal Performance And Productivity Of A New Cultivar Of Brachiaria Brizantha, Valéria P. B. Euclides, Denise B. Montagner, Cacilda B. Valle, Nayana N. Nantes

IGC Proceedings (1977-2023)

Brazil has the competitive advantage of a very dynamic and cost-effective animal production system on pastures over other countries. The pursuit of more productive forages that will result in higher quality beef at a lower cost is justified. As Brachiaria is the most important forage genus utilised in Brazil, an intense search for new cultivars amongst collected and introduced ecotypes from Africa is underway. Following agronomic evaluation of this material in plots, 8 Brachiaria ecotypes were pre-selected. As part of Embrapa`s process of cultivar development, B. brizantha cv. Xaraés, characterised by high productivity (liveweight gain/area), was released in 2003, followed …

Performance Of Young Nellore Bulls Grazing Marandu Grass Pasture At Different Heights, Ricardo A. Reis, Andre L. S. Valente, Sharadinny M. C. Dos Santos, Fernando H. M. De Souza, Telma T. Berchielli, Ana C. Ruggieri, Sabrina S. Santana, Juliana M. Serra

IGC Proceedings (1977-2023)

Brazil is one of the largest beef cattle producers in the world with approximately 200 M head. The Industry relies predominantly on warm-season grass pastures, with approximately 90% of animals finished on pastures.

One of the main factors for the intensification of animal production systems based on pasture is appropriate management. Adjustment of stocking rate to maintain optimum forage allowance is essential. Studies on forage allowance have resulted in a better understanding of the response of forage crops and animals to changes in grazing intensity.

The purpose of this study was to evaluate management strategies for beef cattle systems grazed …

Seasonal Expression Of Apospory In Bahiagrass, Esteban F. Rios, Ann R. Blount, Kevin E. Kenworthy, Carlos A. Acuña, Kenneth H. Quesenberry

IGC Proceedings (1977-2023)

Flowering plants can reproduce sexually (outcrossing and/or selfing) and/or asexually. Sexual reproduction implies the successful completion of meiosis and double fertilisation for the formation of both the embryo and the endosperm. In contrast, gametophytic apomixis is an asexual mode of reproduction through seeds that involves parthenogenetic embryo development from a cytologically unreduced egg cell (2n). Apospory is the process by which unreduced gametophytes are formed after a series of mitotic divisions of somatic cells (2n) in the ovary. This occurs independently from the sexual meiotic process; and therefore, both sexual and apomictic pathways may coexist simultaneously. Apospory is inherited in …

Morphogenic Responses Of Two Brachiaria Genotypes In Response To Clipping Frequency, Ana Flávia G. Faria, Carlos G. S. Pedreira, Diego N. L. Pequeno, Liliane S. Silva, Damião W. Nguluve, Aliedson S. Ferreira

IGC Proceedings (1977-2023)

Tropical grasslands represent an important resource for the Brazilian cattle industry, which is heavily dependent on grazed pastures. Total pasture area in the country totals 196 M ha (23% of the country’s land area) (FAO 2013). The genus Brachiaria represents around 85% of cultivated pastures in Brazil (Moreira et al. 2009), 40% of which are established with B. brizantha cv. Marandu (Barbosa 2006). Mulato II is a new hybrid brachiaria grass cultivar which has been developed to improve agronomic characteristics, broaden the range of adaptation, and to ensure high forage production and nutritive value. It has also been viewed …

Sward Structural Characteristics Of Perennial Peanut Genotypes As Affected By Harvest Frequency, Aliedson S. Ferreira, Carlos G. S. Pedreira, Carla M. Marassatto

IGC Proceedings (1977-2023)

Despite the high potential of tropical forage species, herbage production, nutritive value and animal productivity in Brazilian livestock production systems are lower than what can be obtained from both a biological and operational point of view (Pedreira and Mello 2000, Da Silva and Sbrissia 2000). Even with these limitations, the livestock industry is often able to sustain high productivity levels (animal product per hectare) by using good animal genetics and supplementation. Reducing production costs, however, will likely depend on the identification and incorporation of a high-quality forage resource, in terms of both improving diet quality of grazing animals and sustaining …

Morphophysiological Adaptations Of Brachiaria Humidicola Cultivars Under Grazing, Rodrigo A. Barbosa, Pedro N. C. Amaral, André F. Sbrissia, Thiago T. Camara

IGC Proceedings (1977-2023)

Pastures of Brachiaria humidicola are broadly used in Brazil, especially in soils with low fertility and poor drain-age (Valle et al. 2010). Currently, 3 cultivars are commercially available: Tully, Llanero and BRS Tupi (available since 2012). Despite the extensive use of this species, research has focused primarily on aspects related to herbage and animal production, while only a few studies aimed at understanding morphological adaptations of the plants when subjected to grazing and contrasting environmental conditions.

Therefore, the aim of this work was to evaluate some morphological traits of 2 B. humidicola cultivars when continuously stocked during 2 seasons …

Generalized Matrix Decomposition Regression: Estimation And Inference For Two-Way Structured Data, Yue Wang, Ali Shojaie, Tim Randolph, Jing Ma

UW Biostatistics Working Paper Series

Analysis of two-way structured data, i.e., data with structures among both variables and samples, is becoming increasingly common in ecology, biology and neuro-science. Classical dimension-reduction tools, such as the singular value decomposition (SVD), may perform poorly for two-way structured data. The generalized matrix decomposition (GMD, Allen et al., 2014) extends the SVD to two-way structured data and thus constructs singular vectors that account for both structures. While the GMD is a useful dimension-reduction tool for exploratory analysis of two-way structured data, it is unsupervised and cannot be used to assess the association between such data and an outcome of interest. …

Isolated Point Theorems For Uniform Algebras On Smooth Manifolds, Swarup Ghosh

Faculty Articles & Research

In 1957, Andrew Gleason conjectured that if A is a uniform algebra on its maximal ideal space X and every point of X is a one-point Gleason part for A, then A must contain all continuous functions on X. Gleason’s conjecture was disproved by Brian Cole in 1968. In this paper, we establish a strengthened form of Gleason’s conjecture for uniform algebras generated by real-analytic functions on compact subsets of real-analytic three-dimensional manifolds-with-boundary.

The Belle Ii Physics Book, E. Kou, P. Urquijo, W. Altmannshofer, F. Beajean, G. Bell, M. Beneke, I. I. Bigi, F. Bishara, M. Blanke, C. Bobeth, M. Bona, N. Brambilla, V. M. Braun, J. Brod, A. J. Buras, H. Y. Cheng, C. W. Chiang, M. Ciuchini, G. Colangelo, Milind Purohit, Et. Al.

Faculty Publications

No abstract provided.

Gaze Collaboration Patterns Of Successful And Unsuccessful Programming Pairs Using Cross-Recurrence Quantification Analysis, Maureen Villamor, Ma. Mercedes T. Rodrigo

Department of Information Systems & Computer Science Faculty Publications

A dual eye tracking experiment was performed on pairs of novice programmers as they traced and debugged fragments of code. These programming pairs were categorized into successful and unsuccessful pairs based on their debugging scores. Cross-recurrence quantification analysis (CRQA), an analysis using cross-recurrence plots (CRP), was used to determine whether there are significant differences in the gaze collaboration patterns between these pair categories. Results showed that successful and unsuccessful pairs can be characterized distinctively based on their CRPs and CRQA metrics. This study also attempted to interpret the CRQA metrics in relation to how the pairs collaborated in order to …

Blockchain Based Access Control For Enterprise Blockchain Applications, Lei Xu, Isaac Markus, Subhod I, Nikhil Nayab

Computer Science Faculty Publications

Access control is one of the fundamental security mechanisms of IT systems. Most existing access control schemes rely on a centralized party to manage and enforce access control policies. As blockchain technologies, especially permissioned networks, find more applicability beyond cryptocurrencies in enterprise solutions, it is expected that the security requirements will increase. Therefore, it is necessary to develop an access control system that works in a decentralized environment without compromising the unique features of a blockchain. A straightforward method to support access control is to deploy a firewall in front of the enterprise blockchain application. However, this approach does not …

Land Cover Change Detection In The Urban Catchments Of Dar Es Salaam, Tanzania Using Remote Sensing And Gis Techniques, Philip Mzava, Joel Nobert, Patrick Valimba

Tanzania Journal of Science

In this study, the Maximum Likelihood (ML) classification, Normalized Difference Vegetation Index (NDVI) and Artificial Neural Network (ANN) methods were applied to three (3) Landsat images collected over time (1979, 1998 and 2014), that contained historical land cover features for the urban catchments of Dar es Salaam. Five major land cover classes were identified, mapped, and the land cover changes investigated. The major land cover changes observed from post-classification comparisons of the classified images are: the forest land losing 17.09% of its area in the period 1979-1998 to other land covers, mainly turning to grassland, and from 1998 to 2014, …

Phytoremediation Potential Of Four Heavy Metals In Soil By Chromolaena Odorata (L.) King & Robinson At The Phytotoxicity Screening Benchmarks, Gloria O. Omoregie, Beckley Ikhajiagbe, Geoffery O. Anoliefo

Tanzania Journal of Science

The remediative capacity of Chromolaena odorata with respect to heavy metal induced growth-stress was investigated. This was with a view to providing information on the adaptive mechanisms adopted by the test plant during the phytoremediation of selected heavy metals such as copper, manganese, zinc and cadmium. Stems of C. odorata were planted in soils polluted with  Mn, Zn, Cd, and Cu at the ecological screening benchmark (ESB) of 50 mg/kg (Mn and Zn), 4 mg/kg (Cd) and 100 mg/kg (Cu) of metal per kilogram of soil, in varying concentrations of 0 ESB (control), 1 ESB, 3 ESB and 5 ESB. …

Target-To-Target Interaction In Through-The-Wall Radars Under Path Loss Compensated Multipath Exploitation-Based Signal Model For Sparse Image Reconstruction, Emmanuel K. Kokumo, Baraka Maiseli, Abdi T. Abdalla

Tanzania Journal of Science

Multipath caused by reflections from interior walls of buildings has been a long-standing challenge that affects through-the-wall radar imaging. Multipath creates ghost images that introduce confusion when detecting desired targets. Traditionally, multipath exploitation techniques under the compressive sensing framework have widely been applied to address the challenge. However, the multipath component emanating from target-to-target interactions has not been considered–a consequence that may, under multiple target scenarios, lead to incorrect image interpretation. Besides, far targets experience more attenuation due to free space path loss, hence resulting into target undetectability. This study proposes a signal model, based on multipath exploitation techniques, by …

On Scalar Multiples Of Hypercyclic Operators On Non-Normable And Separable Fréchet Spaces, Melkiory M. Aloyce, Santosh Kumar, Marco Mpimbo

Tanzania Journal of Science

In this paper, we proved that if F is a non-normable and separable Fréchet space without a continuous norm, then there exists an operator T L (F) such that λ T is hypercyclic for any λ   {0} of modulus 1 and has similar set of hypercyclic vectors as T. An illustrative example to the main theorem is also provided.

Modelling And Analysis Of A Holling Type Ii Stage Structured Predator-Prey System In The Presence Of Harvesting, Jacob Lyimo, Nyimvua Shaban, Eunice Mureithi, Thadei Sagamiko

Tanzania Journal of Science

The effect of harvesting and predation on a Holling type II stage-structured predator-prey system with assumption that harvesting and predation happen only to mature preys was investigated. Stability of interior point was analysed using Routh Hurwith Criterion. Numerical simulations were carried out. The results show that harvesting and predation have strong negative impacts on population dynamics of stage structured predator-prey system.

Effects Of Seasons And Zonation On Biochemical Contents Of Two Seagrass Species Along Dar Es Salaam Coast, Tanzania, Wamwi M. Mbaga, Esther F. Mvungi

Tanzania Journal of Science

Accumulation and allocation of biochemicals in plants are affected by various factors. The influence of seasons and vertical zonation on biochemical contents of seagrasses Cymodocea rotundata and Thalassia hemprichii from Mjimwema seagrass meadow along the coast of Dar es Salaam were assessed. Samples were collected in 2016 during wet/rainy (April–May) and dry (June–July) seasons. Concentrations of crude protein, soluble carbohydrates, phosphorus, lipid, and proline were determined using standard methods. Significant higher levels of phosphorus, lipid, protein and proline were observed during the dry season than in wet season (p < 0.05). Likewise, seagrass population occurring at the shore zone expressed higher levels of biochemical contents than those found at the subtidal zones. The highest concentration of protein was recorded in Thalassia hemprichii (5.8 mg/g dw)), while those of lipid and carbohydrates (27.1 and 53.1 mg/g dw, respectively) were recorded in Cymodocea rotundata. The two species studied did not vary significantly in their biochemical concentrations in both seasons. Generally it was observed that the concentrations of studied biochemicals were up-regulated during the dry season and varied depending on the locations where the seagrass grow. Thus, both season and zonation played roles in biochemical accumulation in the seagrasses understudy, however not interactively.

Mixed Mode Device-To-Device Communication Scheme For Congestion Reduction And Channel Usage Optimization In 5g Cellular Networks, Chiza M. Christophe, Omar F. Hamad, Libe V. Massawe, Abdi T. Abdalla

Tanzania Journal of Science

Device-to-Device (D2D) communication schemes have gained more attention in cellular networks particularly in normalization process of the upcoming 5G networks. They have been investigated in core network offloading, congestion reduction and channel usage optimization.  The two last cases are among the major constraints in current cellular networks and are the main concerns of this paper. The paper presents a mixed mode D2D communication scheme to decentralize data collection between devices and the base station in order to reduce the number of direct connections at the base station of ultra-dense cells characterized by different levels of channel utilizations or target data …

Preliminary Palynology Of The Karoo Equivalent Tanga Beds, Coastal Tanzania: Insights On Preservation, Age And Depositional Environments, Stephen Peter Magohe

Tanzania Journal of Science

The major challenge to the current understanding of the stratigraphy of the Tanga Basin is scarcity of biostratigraphy age-control data. A number of palynomorphs retrieved from core samples of the Tanga Beds and analysed for palynology are here presented. These include bisaccate pollen grains belonging to the Alisporites-Falcisporites complex, making about 55% average of the total assemblage. The rest of the assemblage comprises other palynomorphs (pollen and spores) and phytoclasts. The miospores documented from the studied samples have poor to fairly good preservation; the organic residues (non-pollen palynomorphs) are excellently preserved. Based on palynologic evidences, and the presence of fossil …

Quantitative Assessment Of Resistivity Anisotropy In Evaluation Of Laminated Shaly Sand Hydrocarbon Reservoirs–A Case Study In The Barents Sea, Norway, Ernest S. Mulaya

Tanzania Journal of Science

Resistivity anisotropy in shaly sand lamination sequences affects the hydrocarbon evaluation in multiple dimensions of petrophysical logs. Currently, vertical resistivity (Rv) and horizontal resistivity (Rh) from 3D triaxial induction measurements can be applied simultaneously to resolve these petrophysical impacts. In this paper, an extensive analysis is offered with a focus on the hydrocarbon evaluation based on advanced petrophysical logs from a well. A critical analysis is done on the three comparable cases including clean formation as a base case, shaly sand case and laminated shaly sand case towards resolving resistivity anisotropy in a typical shaly sand laminated reservoir. The analysis …

Total Electron Content Prediction Model Using The Artificial Neural Networks Over The Eastern Africa Region, Emmanuel D. Sulungu, Christian B.S. Uiso

Tanzania Journal of Science

In this paper, development of a model using NN technique for prediction of GPS TEC over the Eastern Africa region is presented. TEC data was obtained from the Africa array and IGS network of ground based dual-frequency GPS receivers from 18 stations within the East African region. It covers approximately the area from ~2.6°N to ~26.9°S in magnetic latitudes and from ~95°E to ~112oE in magnetic longitudes. The input layer of the developed model consisted of seven neurons which were selected by considering the parameters that are known to affect the TECv data. The results showed that when the number …

Synthesis Of Semiochemicals And Related Fine Chemicals From Cashew Nut Shell Liquid, Godfrey Pius, Quintino A Mgani

Tanzania Journal of Science

This paper reports on syntheses of 3-hydroxybenzaldehyde (1) and tetradecanal (2) from the same renewable starting material (cashew nut shell liquid or CNSL), thus demonstrating the potential of the agro-waste cashew nut shells (CNS) as a source of valuable fine and industrial chemicals. The strategy employed in accomplishing the synthesis started with extraction of CNSL followed by isolation of anacardic acid (4) and decarboxylation to give cardanol (5). Compound 5 was hydrogenated followed by protection of phenolic group to give 3-pentadecylphenyl acetate (7). Benzylic oxidation of compound 7 followed by reduction and dehydration resulted into formation of 3-(pentadec-1-en-1-yl)phenol (9). Ozonolysis …

Generation Of Highly Ordered 3d Vivid Monochromatic Coloured Photonic Crystal Films Using Evaporative Induced Technique, Ikhazuagbe H. Ifijen, Esther U. Ikhuoria

Tanzania Journal of Science

Structural coloured crystal films have attracted immense attention because of numerous applications like optical sensing, anti-counterfeiting and photonic fabrics.  Herein, we successfully generated highly periodic three-dimensional (3D) monochromatic structural crystal films with brown, turquoise, blue and yellow colourations from as-synthesized poly(styrene-methyl methacrylate-acrylic acid) or P(St-MMA-AA) colloidal latex via the evaporative induced self-assembly technique. The colours were controlled through the modulation of their crystal lattice by varying their microspheres diameter from 180 nm, 120 nm, and 260 nm to 150 nm. Scanning electron microscope and atomic force microscope (SEM/AFM) analyses showed that the photonic crystal particles readily assembled into an impeccable …