Recent Submissions

  • Exploring the effect of exercise training on testicular function

    Matos, Barbara; Howl, John; Fardilha, Margarida (Springer, 2018-09-08)
    Purpose The impact of exercise training on testicular function is relatively ill-defined. To gain new insights into this important topic, published data, deriving from both humans and animal studies, were critically analyzed. Results and conclusions The effects of exercise on the hypothalamus–pituitary–gonadal axis, influenced by the type, intensity and duration of the exercise program, can be evaluated in terms of total and free testosterone and/or luteinizing hormone and follicle-stimulating hormone serum levels and sperm parameters. High-intensity exercise promotes a common decrease in these parameters, and therefore, negatively impacts upon testicular function. However, published data for moderate-intensity exercise training are inconsistent. Conversely, there is consistent evidence to support the benefits of exercise training to prevent and/or counteract the impairment of testis function caused by aging, obesity and doxorubicin treatment. This positive effect is likely the consequence of decreased oxidative stress and inflammatory status. In the future, it will be important to clarify the molecular mechanisms which explain these reported discrepancies and to establish guidelines for an active lifestyle to promote healthy testicular function.
  • Species

    Kaburu, Stefano S. K (Springer, 2019-02-08)
  • Rank acquisition in rhesus macaque yearlings following permanent maternal separation: The importance of the social and physical environment

    Wooddell, Lauren J.; Kaburu, Stefano S. K; Murphy, Ashley M.; Suomi, Stephen J.; Dettmer, Amanda M. (Wiley, 2017-08-18)
    Rank acquisition is a developmental milestone for young primates, but the processes by which primate yearlings attain social rank in the absence of the mother remain unclear. We studied 18 maternally reared yearling rhesus macaques (Macaca mulatta) that differed in their social and physical rearing environments. We found that early social experience and maternal rank, but not individual traits (weight, sex, age), predicted dominance acquisition in the new peer‐only social group. Yearlings also used coalitions to reinforce the hierarchy, and social affiliation (play and grooming) was likely a product, rather than a determinant, of rank acquisition. Following relocation to a familiar environment, significant rank changes occurred indicating that familiarity with a physical environment was salient in rank acquisition. Our results add to the growing body of literature emphasizing the role of the social and physical environment on behavioral development, namely social asymmetries among peers.
  • Handling newborn monkeys alters later exploratory, cognitive, and social behaviors

    Simpson, Elizabeth A.; Sclafani, Valentina; Paukner, Annika; Kaburu, Stefano S. K; Suomi, Stephen J.; Ferrari, Pier F (Elsevier, 2017-08-18)
    Touch is one of the first senses to develop and one of the earliest modalities for infant-caregiver communication. While studies have explored the benefits of infant touch in terms of physical health and growth, the effects of social touch on infant behavior are relatively unexplored. Here, we investigated the influence of neonatal handling on a variety of domains, including memory, novelty seeking, and social interest, in infant monkeys (Macaca mulatta; n = 48) from 2 to 12 weeks of age. Neonates were randomly assigned to receive extra holding, with or without accompanying face-to-face interactions. Extra-handled infants, compared to standard-reared infants, exhibited less stress-related behavior and more locomotion around a novel environment, faster approach of novel objects, better working memory, and less fear towards a novel social partner. In sum, infants who received more tactile stimulation in the neonatal period subsequently demonstrated more advanced motor, social, and cognitive skills—particularly in contexts involving exploration of novelty—in the first three months of life. These data suggest that social touch may support behavioral development, offering promising possibilities for designing future early interventions, particularly for infants who are at heightened risk for social disorders.
  • Micropechis ikaheka (Elapidae) in Papua, Indonesia: A study of diet and cannibalism

    Krey, Keliopas; O'Shea, Mark; Farajallah, Achmad; Setiadi, Dede; Suryobroto, Bambang (Societas Europaea Herpetologica, 2015-05-26)
    Snakes are primary predators in many terrestrial, aquatic, and marine communities. As predators, the lives of wild snakes are therefore closely related to feeding ecology. Feeding ecology is related not only to food availability but also to the body sizes of the predators and prey (Cundall and Greene, 2000). Studying the diet of a snake species is critical to our knowledge of the ecology of the snake at individual, population and community levels. Ecological studies of snake diets are also very important for a better understanding of the relationships between snakes and other organisms in the ecosystem (Su et al., 2005).
  • Atmin modulates Pkhd1 expression and may mediate autosomal recessive polycystic kidney disease (ARPKD) through altered non-canonical Wnt/planar cell polarity (PCP) signalling

    Richards, Taylor; Modarage, Kavindiya; Dean, Charlotte; McCarthy-Boxer, Aidan; Hilton, Helen; Esapa, Chris; Wilson, Patricia; Goggolidou, Paraskevi (Elsevier, 2018-11-07)
    Autosomal Recessive Polycystic Kidney Disease (ARPKD) is a genetic disorder with an incidence of ~1:20,000 that manifests in a wide range of renal and liver disease severity in human patients and can lead to perinatal mortality. ARPKD is caused by mutations in PKHD1, which encodes the large membrane protein, Fibrocystin, required for normal branching morphogenesis of the ureteric bud during embryonic renal development. The variation in ARPKD phenotype suggests that in addition to PKHD1 mutations, other genes may play a role, acting as modifiers of disease severity. One such pathway involves non-canonical Wnt/Planar Cell Polarity (PCP) signalling that has been associated with other cystic kidney diseases, but has not been investigated in ARPKD. Analysis of the AtminGpg6 mouse showed kidney, liver and lung abnormalities, suggesting it as a novel mouse tool for the study of ARPKD. Further, modulation of Atmin affected Pkhd1 mRNA levels, altered non-canonical Wnt/PCP signalling and impacted cellular proliferation and adhesion, although Atmin does not bind directly to the C-terminus of Fibrocystin. Differences in ATMIN and VANGL2 expression were observed between normal human paediatric kidneys and age-matched ARPKD kidneys. Significant increases in ATMIN, WNT5A, VANGL2 and SCRIBBLE were seen in human ARPKD versus normal kidneys; no substantial differences were seen in DAAM2 or NPHP2. A striking increase in E-cadherin was also detected in ARPKD kidneys. This work indicates a novel role for non-canonical Wnt/PCP signalling in ARPKD and suggests ATMIN as a modulator of PKHD1.
  • The taxonomic history of the enigmatic Papuan snake genus Toxicocalamus (Elapidae: Hydrophiinae), with the description of a new species from the Managalas Plateau of Oro Province, Papua New Guinea, and a revised dichotomous key

    O'Shea, Mark; Allison, Allen; Kaiser, Hinrich (Societas Europaea Herpetologica, 2018-11-15)
    We trace the taxonomic history of Toxicocalamus, a poorly known genus of primarily vermivorous snakes found only in New Guinea and associated island archipelagos. With only a relatively limited number of specimens to examine, and the distribution of those specimens across many natural history collections, it has been a difficult task to assemble a complete taxonomic assessment of this group. As a consequence, research on these snakes has undergone a series of fits and starts, and we here present the first comprehensive chronology of the genus, beginning with its original description by George Albert Boulenger in 1896. We also describe a new species from the northern versant of the Owen Stanley Range, Oro Province, Papua New Guinea, and we present a series of comparisons that include heretofore underused characteristics, including those of unusual scale patterns, skull details, and tail tip morphology. Defined by the smallest holotype in the genus, the new species is easily differentiated from all other Toxicocalamus by a combination of the following eidonomic characters: fused prefrontal-internasal scute; single preocular, separate, not fused with prefrontal; minute circular, counter-sunk naris in the centre of a large, undivided, nasal scute; paired postoculars; single anterior temporal and paired posterior temporals; six supralabials, with 3rd and 4th supralabial contacting the orbit; dorsal scales in 15-15-15 rows; 235 ventral scales, 35 paired subcaudal scales; paired cloacal scales preceded by paired precloacal scales; and a short, laterally slightly compressed, ‘Ultrocalamus-type’ tail, terminating in a short conical scale. Differences from congeners in skull morphology include a reduced anterior extent of the parasphenoid, termination of the palatine tooth row at the anterior level of the parasphenoid, extent and shape of the premaxilla, shape and size of the prootics, extent and shape of the exoccipitals and occipital condyles, and features of the atlas-axis complex. This is the fifteenth species in the genus Toxicocalamus.
  • The crucial role of leucine concentration on spray dried mannitol-leucine as a single carrier to enhance the aerosolization performance of Albuterol sulfate

    Molina, Carlos; Kaialy, Waseem; Nokhodchi, Ali (Elsevier, 2018-11-09)
    Generally, DPI formulations show low fine particle fraction (FPF) due to poor detachment of drug particles from carrier during inhalation. l-Leucine, with varying concentrations (ranging from 0 to 10% w/w), were introduced into a 60%w/v mannitol solution where the solutions were then spray dried to achieve a new processed carrier. The spray dried samples were blended with Albuterol sulfate to determine the efficacy of their aerosolization performance. Analyzing each formulation was completed via the implementation of numerous analytical techniques such as particle size distribution analysis via laser diffraction, differential scanning calorimetry (DSC), scanning electron microscope (SEM), powder X-Ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, and an in vitro deposition study. It was shown the concentration of leucine in spray dried is really crucial to achieve the highest FPF possible. The highest FPF was obtained for the samples containing 10% w/w leucine which was 52.96 ± 5.21%. It was interesting to note that the presence of leucine produced different polymorphic forms for mannitol. Moreover, through this study, the authors were able to conclude that mannitol can serve as an alternative carrier in DPI formulations containing Albuterol sulfate tailored for lactose intolerant patients.
  • Biomineralisation performance of bacteria isolated from a landfill in China

    Rajasekar, Adharsh; Wilkinson, Stephen; Sekar, Raju; Bridge, Jonathan; Medina-Roldán, Eduardo; K.S. Moy, Charles (2018-08-27)
    We report an investigation of microbially induced carbonate precipitation by seven indigenous bacteria isolated from a landfill in China. Bacterial strains were cultured in a medium supplemented with 25 mmol/L calcium chloride and 333 mmol/L urea. The experiments were carried out at 30 °C for 7 days with agitation by a shaking table at 130 r/min. Scanning electron microscopic and X-ray diffraction analyses showed variations in calcium carbonate polymorphs and mineral composition induced by all bacterial strains. The amount of carbonate precipitation was quantified by titration. The amount of carbonate precipitated in the medium varied among isolates, with the lowest being Bacillus aerius rawirorabr15 (LC092833) precipitating around 1.5 times more carbonate per unit volume than the abiotic (blank) solution. Pseudomonas nitroreducens szh_asesj15 (LC090854) was found to be the most efficient, precipitating 3.2 times more carbonate than the abiotic solution. Our results indicate that bacterial carbonate precipitation occurred through ureolysis and suggest that variations in carbonate crystal polymorphs and rates of precipitation were driven by strain-specific differences in urease expression and response to the alkaline environment. These results and the method applied provide benchmarking and screening data for assessing the bioremediation potential of indigenous bacteria for containment of contaminants in landfills.
  • The taxonomic history of Indo-Papuan groundsnakes, genus Stegonotus Duméril et al., 1854 (Colubridae), with some taxonomic revisions and the designation of a neotype for S. parvus (Meyer, 1874)

    Kaiser, Christine; Kaiser, Hinrich; O'Shea, Mark (Magnolia Press, 2018-07-16)
    Since its conceptualization in 1854, 29 species of the colubrid genus Stegonotus have been recognized or described, of which 15 (admiraltiensis, batjanensis, borneensis, cucullatus, derooijae, diehli, florensis, guentheri, iridis, heterurus, melanolabiatus, modestus, muelleri, parvus, poechi) are still considered valid today. Original species descriptions for the members of this genus were published in Dutch, English, French, German, and Italian and, perhaps as a consequence of these polyglot origins, there has been a considerable amount of confusion over which species names should be applied to which populations of Stegonotus throughout its range across Borneo, the Philippines, Wallacea, New Guinea, Australia, and associated archipelagos. In addition, the terminology used to notate characteristics in the descriptions of these forms was not uniform and may have added to the taxonomic confusion. In this paper, we trace in detail the history of the type specimens, the species, and the synonyms currently associated with the genus Stegonotus and provide a basic, species-specific listing of their characteristics, derived from our examination of over 1500 museum specimens. Based on our data, we are able to limit the distribution of S. modestus to the islands of Ambon, Buru, and Seram in the central Moluccas of Indonesian Wallacea. We correct the type locality of S. cucullatus to the Manokwari area on the Bird’s Head Peninsula of West Papua, Indonesian New Guinea and designate a neotype for S. parvus, a species likely to be a regional endemic in the Schouten Archipelago of Cenderawasih Bay (formerly Geelvink Bay), Indonesian New Guinea. We unequivocally identify and explain the problematic localities of the type specimens of S. muelleri and Lycodon muelleri, which currently reside in the same specimen jar. We remove L. aruensis and L. lividum from the synonymy of S. modestus and recognize them as S. aruensis n. comb. and S. lividus n. comb., respectively. We remove S. keyensis and Zamenophis australis from the synonymy of S. cucullatus and recognize them as S. keyensis n. comb. and S. australis n. comb., respectively. We further remove S. reticulatus from the synonymy of S. cucullatus, S. dorsalis from the synonymy of S. diehli, and S. sutteri from the synonymy of S. florensis. We designate lectotypes for S. guentheri, S. heterurus, S. lividus, and S. reticulatus. Lastly, we introduce S. poechi, a valid species not mentioned in the scientific literature since its description in 1924. This brings the diversity in the genus Stegonotus to 22 species. We also caution that in a complex group of organisms like Stegonotus any rush to taxonomic judgment on the basis of molecular and incomplete morphological data sets may perpetuate errors and introduce incongruities. Only through the careful work of connecting type material with museum specimens and molecular data can the taxonomy and nomenclature of complex taxa be stabilized.
  • Metamaterial Superlenses Operating at Visible Wavelength for Imaging Applications

    Haxha, Shyqyri; AbdelMalek, Fathi; Ouerghi, Faouzi; Charlton, Martin; Aggoun, Amar; Fang, Xu (Nature Research, 2018-10-31)
    In this paper, a novel design for a metamaterial lens (superlens) based on a Photonic Crystal (PC) operating at visible wavelengths is reported. The proposed superlens consist of a gallium phosphide (GaP) dielectric slab waveguide with a hexagonal array of silver rods embedded within the GaP dielectric. In-house 2DFDTD numerical method is used to design and optimize the proposed superlens. Several superlenses are designed and integrated within a same dielectric platform, promoting the proof-of-concept (POC) of possible construction of an array of superlenses (or sub-lenses to create an M-Lens) for light field imaging applications. It is shown that the concavity of the superlens and positioning of each sub-lens within the array strongly affects the performances of the image in terms of resolution. Defects and various geometrical shapes are introduced to construct and optimize the proposed superlenses and increase the quality of the image resolution. It is shown that the orientation of the active region (ellipse) along x and y axis has tremendous influence on the quality of image resolution. In order to investigate the performance characteristics of the superlenses, transmitted power is calculated using 2D FDTD for image projections at various distances (in x and y plane). It is also shown, how the proposed superlens structures could be fabricated using standard micro fabrication techniques such as electron beam lithography, inductively coupled Reactive ion etching, and glancing angle evaporation methods. To the best of our knowledge, these are the first reported POC of superlenses, integrated in a monolithic platform suitable for high imaging resolution that can be used for light field imaging applications at visible wavelength. The proposed superlenses (integrated in a single platform M-Lens) will have tremendous impact on imaging applications.
  • A Guide to the snakes of Papua New Guinea: The first comprehensive guide to the snake fauna of Papua New Guinea

    O'Shea, Mark (Independent Publishing, 1996-11-02)
    A complete guide to the snakes of the island of New Guinea (with particular emphasis on the eastern half constituting the sovereign state of Papua New Guinea) and the islands to the east, e.g. Bismarck, Admiralty, d'Entrecasteaux, Louisiade and North Solomons Archipelagoes. Although out of print and also now out of date, this is still the definitive and much sought guide to the snake fauna of this region. It includes a section of snakebite first aid and hospital treatment by Drs David A Warrell and David G Lalloo.
  • The Book of snakes

    O'Shea, Mark (Ivy Press, 2018-10-11)
    There are over 3,700 species of snake found on every continent except for Antarctica, ranging in size from Barbados’ tiny threadsnake to Southeast Asia’s massive reticulated python. More than any other creature snakes are surrounded by dark, compelling myths and legend, unsurprising since many constrict their prey to death, or kill with a venomous bite, using a diverse armory of venoms that affect the blood, tissues, organs, and respiration. However, it is especially true of snakes that the closer you observe them, the more exquisite they are in their intricate geometry of pattern, the fine texture of the overlapping scales, and the intricacies of their multifarious lifestyles. The Book of Snakes profiles 600 significant species from all 32 families—one in six of all known species—to create a beautiful collector’s piece that is both a significant resource for enthusiasts and scholars, and the most visually stimulating guide on the market.
  • Ending the drought: New strategies for improving the flow of affordable, effective antivenoms in Asia and Africa

    Williams, David J.; Gutiérrez, José-María; Calvete, Juan J.; Wüster, Wolfgang; Ratanabangangkoon, Kavi; Paiva, Owen; Brown, Nicholas I.; Casewell, Nicholas R.; Harrison, Robert A.; Rowley, Paul, D.; O'Shea, Mark; Jensen, Simon D.; Winkel, Kenneth D.; Warrell, David A. (Elsevier, 2011-08-24)
    The development of snake antivenoms more than a century ago should have heralded effective treatment of the scourge of snakebite envenoming in impoverished, mostly rural populations around the world. That snakebite still exists today, as a widely untreated illness that maims, kills and terrifies men, women and children in vulnerable communities, is a cruel anachronism. Antivenom can be an effective, safe and affordable treatment for snakebites, but apathy, inaction and the politicisation of public health have marginalized both the problem (making snakebite arguably the most neglected of all neglected tropical diseases) and its solution. For lack of any coordinated approach, provision of antivenoms has been pushed off the public health agenda, leading to an incongruous decline in demand for these crucial antidotes, excused and fed by new priorities, an absence of epidemiological data, and a poor regulatory framework. These factors facilitated the infiltration of quality products that degrade user confidence and undermine legitimate producers. The result is that tens of thousands are denied an essential life-saving medicine, allowing a toll of human suffering that is a summation of many individual catastrophes. No strategy has been developed to address this problem and to overcome the intransigence and inaction responsible for the global tragedy of snakebite. Attempts to engage with the broader public health community through the World Health Organisation (WHO), GAVI, and other agencies have failed. Consequently, the toxinology community has taken on a leadership role in a new approach, the Global Snakebite Initiative, which seeks to mobilise the resources, skills and experience of scientists and clinicians for whom venoms, toxins, antivenoms, snakes and snakebites are already fields of interest. Proteomics is one such discipline, which has embraced the potential of using venoms in bio-discovery and systems biology. The fields of venomics and antivenomics have recently evolved from this discipline, offering fresh hope for the victims of snakebites by providing an exciting insight into the complexities, nature, fundamental properties and significance of venom constituents. Such a rational approach brings with it the potential to design new immunising mixtures from which to raise potent antivenoms with wider therapeutic ranges. This addresses a major practical limitation in antivenom use recognised since the beginning of the 20th century: the restriction of therapeutic effectiveness to the specific venom immunogen used in production. Antivenomic techniques enable the interactions between venoms and antivenoms to be examined in detail, and if combined with functional assays of specific activity and followed up by clinical trials of effectiveness and safety, can be powerful tools with which to evaluate the suitability of current and new antivenoms formeeting urgent regional needs.We propose two mechanisms through which the Global Snakebite Initiative might seek to end the antivenom drought in Africa and Asia: first by establishing amultidisciplinary,multicentre, international collaboration to evaluate currently available antivenoms against the venoms of medically important snakes from specific nations in Africa and Asia using a combination of proteomic,antivenomic and WHO-endorsed preclinical assessment protocols, to provide a validated evidence base for either recommending or rejecting individual products; and secondly by bringing the power of proteomics to bear on the design of new immunising mixtures to raise Pan-African and Pan-Asian polyvalent antivenoms of improved potency and quality. These products will be subject to rigorous clinical assessment. We propose radically to change the basis upon which antivenoms are produced and supplied for the developing world. Donor funding and strategic public health alliances will be sought to make it possible not only to sustain the financial viability of antivenom production partnerships, but also to ensure that barrier to the treatment of this important, but grossly neglected public health emergency.
  • Courtship entanglements: a first report of mating behavior and sexual dichromatism in the Southeast Asian keel-bellied whipsnake, Dryophiops rubescens

    Kaiser, Hinrich; Johnny, Kim; O'Shea, Mark (Herpetology Notes, 2012-09-01)
    We describe the first observations of courtship behavior and sexual dichromatism in the keel-bellied whipsnake, Dryophiops rubescens, from an encounter near Sandakan, eastern Sabah, Borneo, Malaysia. During this behavior, two males and a female were longitudinally intertwined, with the males jockeying for position along the body of the female. This “mating braid” lasted for well over 1 h, with the entwined snakes moving a distance of over 10 m together. While polygynous mating is known from other snake species, direct observations of mating behaviors in Southeast Asian colubrids are extremely rare. These observations also revealed the presence of sexual dichromatism in D. rubescens, with darker head coloration present in the males.
  • Heavy metal removal using alkali activated kaolinite in the Cao-Al2O3-Sio2- H2O system

    Rios, Carlos A; Williams, Craig D; Fullen, Michael (MedCrave, 2017-11-30)
    The transformation of kaolinite was examined at 175°C for 24 h in the CaO-Al2O3- SiO2-H2O (CASH) system, which is important in cement science and especially in, cement chemistry and is closely related to the pozzolanic reaction, the CaO-aggregate reaction and the glass fibre reinforcement of hardened cement. The hydration products were characterized by X-ray diffraction, scanning electron microscopy, Fourier transformed infrared spectroscopy, Magic Angle Spinning Nuclear Magnetic Resonance and thermogravimetric analysis in order to elucidate their mineral chemistry and microstructure. Results reveal that several poorly crystalline phases were formed, with un-reacted Ca(OH)2 appearing at shorter reaction times. Hydrogarnet tends to form more rapidly than tobermorite. It was transformed into aluminium-substituted tobermorite with curing time. A batch experimental study confirmed that kaolinitebased calcium silicate hydrates are effective for the treatment of acid mine drainage, particularly in removing metal ions and ammonium
  • Academic anxiety and its effects on academic performance

    Mirawdali, Shangal; Morrissey, Hana; Ball, Patrick (International Journal of Current Research, 2018-06-28)
    Academic anxiety is a well-established, significant predictor of academic performance. Students with high levels of anxiety are unable to perform at the best of their ability. The purpose of this study was to determine the extent of academic anxiety and its effects on academic performance and explore if social and family sources of anxiety have effects on academic performance. This was a cross-sectional study design utilising questionnaire based on pre-validated tools was used to determine the extent of academic anxiety and evaluate its effect on students with high and low academic performance. A sample of 132 pharmacy undergraduates from stages 3 and 4 enrolled at the University of Wolverhampton, participated in this project. Academic performance was significantly associated with factors such as test anxiety, academic competence and time management skills. A high proportion of the study population indicated low academic performance due to perceived course load and amount of study material assigned for each examination. A positive relationship was observed between social and family sources of anxiety and academic performance and stressors. This study also demonstrated that demographic variables, such as family history of anxiety and different stages may have positive or negative effect on academic performance. This study revealed the high level of academic anxiety among the MPharm undergraduates study sample and identified some influential sources which need to be addressed to improve students’ experience. It is important to develop strategies to facilitate students coping strategies and skills with academic life in order to improve future performance.
  • Genomic epidemiology of clinical Campylobacter spp. at a single health trust site

    Dunn, S.J.; Pascoe, B.; Turton, J.; Fleming, V.; Diggle, M.; Sheppard, S.K.; McNally, A.; Manning, G. (2018-10-11)
    Campylobacter is the leading cause of bacterial enteritis in the developed world, and infections with the organism are largely sporadic in nature. Links between sporadic cases have not been established, with the majority of infections thought to be caused by genetically distinct isolates. Using a read-mapping approach, 158 clinical isolates collected during 2014 from the greater Nottinghamshire area were analysed to assess the local population structure and investigate potential case linkages between sporadic cases of campylobacteriosis. Four instances (2.5 %) of case linkage were observed across the dataset. This study demonstrates that case linkage does occur between sporadic Campylobacter infections, and provides evidence that a dual multi-locus sequence typing/within-lineage single nucleotide polymorphism typing approach to Campylobacter genomic epidemiology provides a benefit to public-health investigations.
  • Impacts of rising temperature, carbon dioxide concentration and sea level on wheat production in North Nile delta

    Kheir, A.; El Baroudy, A.A.; Aiad, M.A.; Zoghdan, M.G.; Abd El-Aziz, M.A.; Ali, M.G.M.; Fullen, M.A. (Elsevier B.V, 2018-10-16)
    Climate change poses a serious threat to arid and low elevation coastal zones. Kafrelsheikh governorate, as a large agricultural and coastal region on the Egyptian North Nile Delta, is one of the most vulnerable areas to higher temperature and global sea level rise. Two DSSAT wheat models (CERES and N-Wheat) were calibrated using a local cultivar (Misr3) grown under irrigated conditions in Egypt. Experimental data of two successive growing seasons during 2014/2015 and 2015/2016 were used for calibration using different treatments of irrigation, planting dates and fertilization. Both models simulated the phenology and wheat yield well, with root mean square deviation of b10%, and d-index N 0.80. Climate change sensitivity analysis showed that rising temperature by 1 °C to 4 °C decreased wheat yield by 17.6%. However, elevated atmospheric CO2 concentrations increased yield and could overtake some of the negative temperature responses. Sea level rise by 2.0 m will reduce the extent of agricultural land on the North Nile Delta of Egypt by ~60% creating an additional challenge to wheat production in this region.
  • Design of Delayed Fractional State Variable Filter for Parameter Estimation of Fractional Nonlinear Models

    Alla, Walid; Zajic, Ivan; Uddin, Kotub; Shen, Zhonghua; Marco, James; Burnham, Keith J. (Springer, 2018-08-17)
    This paper presents a novel direct parameter estimation method for continuous-time fractional nonlinear models. This is achieved by adapting a filter-based approach that uses the delayed fractional state variable filter for estimating the nonlinear model parameters directly from the measured sampled input–output data. A class of fractional nonlinear ordinary differential equation models is considered, where the nonlinear terms are linear with respect to the parameters. The nonlinear model equations are reformulated such that it allows a linear estimator to be used for estimating the model parameters. The required fractional time derivatives of measured input–output data are computed by a proposed delayed fractional state variable filter. The filter comprises of a cascade of all-pass filters and a fractional Butterworth filter, which forms the core part of the proposed parameter estimation method. The presented approaches for designing the fractional Butterworth filter are the so-called, square root base and compartmental fractional Butterworth design. According to the results, the parameters of the fractional-order nonlinear ordinary differential model converge to the true values and the estimator performs efficiently for the output error noise structure.

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