229 research outputs found
CHARACTERIZATION OF PROTEIN SOURCES AND THEIR EFFECTS ON BROILER PERFORMANCE, DIGESTIVE TRACT MORPHOLOGY AND CAECAL FERMENTATION METABOLITES
The goal of this thesis was to characterize protein sources and evaluate their effects on broiler performance, digestive tract morphology and caecal fermentation. Understanding the digestion kinetics of high protein ingredients is an important step in elucidating the impact protein sources have on poultry performance and health. An in vitro assay was used to characterize the digestion kinetics of feed ingredients fed to broilers. The assay predicted the rapidly, slowly and undigested protein fraction of a variety of ingredients, and their digestion rate and extent. Compared to corn distiller dried grain with solubles, soybean meal and fish meal crude protein (CP) was digested more rapidly and to a larger extent. The rate and extent of protein digestion in feed ingredients were also evaluated using broiler chickens, and further the ileal digesta CP was characterized. Protein sources varied in rate and extent of CP and amino acid (AA) digestibility, distal ileum digesta residual AA, and total and soluble CP content. Fish meal, corn gluten meal and soybean meal had similar CP and AA extent of digestion in vivo. Among the protein sources, fish meal had the highest digestion rate for most AA. The total and soluble CP in the distal ileal content of birds fed protein sources ranged from 54 to 1466 and 6 to 347 mg, respectively.
When broilers were vaccinated for coccidiosis and fed antibiotic free diets, dietary protein level (PL) and the ratio of indigestible protein (IDP) fraction affected broiler performance and meat yield. The disease status of the birds and the level of digestible AA in the diets influenced the bird’s response to dietary IDP. The level of caecal metabolites depended on dietary protein source, disease status of the birds and PL. In conclusion, data generated on in vitro and in vivo protein digestion kinetics provide an opportunity to categorize feed ingredients and use this information to establish the impact of these characteristics on broiler nutrition. Dietary PL and IDP affected broiler performance and meat yield when birds were vaccinated for coccidiosis and this was related to the characteristics of the protein sources present in the diets
Pemanfaatan Energi Inersia Fly Wheel untuk Menstabilkan Tegangan Keluaran Generator DC Shunt
Energi terbarukan adalah sumber energi alam yang dapat dengan cepat pulih kembali melalui proses yang alami. Energi terbarukan seperti  energi potensial air dapat dikonversi  menjadi energi gerak dan dalam prosesnya terjadi fluktuatif energi sehingga untuk menstabilkan energi gerak dibutuhkan fly wheel. Fly wheel yang berputar menyimpan energi inersia dan dapat diubah  menjadi energi listrik. Pada penelitian ini energi yang tersimpan pada fly wheel dimanfaatkan untuk menstabilkan tegangan keluaran generator dc. Hasil pengujian dengan masa fly wheel 45.7 kg, diameter 50 cm, tegangan output generator  sebesar 11.09 volt menjadi 10.22 volt atau mengalami penurunan tegangan 0.87 volt atau sebesar 7.84 %.., sedangkan pengujian pada kondisi generator tidak menggunakan fly wheel tegangan keluaran mengalami penurunan dari 21.55 volt menjadi 13.25 volt atau sebesar 38.51 %. Pengujian kestabilan tegangan generator juga mempengaruhi daya keluaran generator yaitu saat tidak menggunakan fly wheel cenderung tidak stabil, pada saat pencuplikan  dari 0 -10 detik kondisi off time prime mover  daya keluaran generator menurun dari 13,36 menjadi 3,81 watt ,sedangkan pada saat menggunakan fly wheel cenderung stabil, misalnya pada pengujian masa fly wheel 45,7 kg daya keluaran generator antara 6.25 sampai 6.87 watt
Pesquisa de Salmonella spp e coliformes termotolerantes em carcaças de frangos in natura comercializados no Distrito Sanitário V da Cidade do Recife - PE
Objetivou-se com este trabalho pesquisar a presença de Salmonella spp. e coliformes termotolerantes em carcaças de frango in natura provenientes de estabelecimentos cadastrados pela Vigilância Sanitária do Recife - PE, distribuídos no Distrito Sanitário V da referida cidade, e a viabilidade das mesmas para o consumo, tendo como parâmetros os valores microbiológicos estabelecidos na RDC nº 12/2001 e RDC nº 13/2001. As amostras foram obtidas de 24 estabelecimentos que as comercializavam expostas à temperatura ambiente, e enviadas ao Laboratório Municipal de Saúde Pública do Recife onde, posteriormente, foram submetidas às análises microbiológicas na divisão de Bromatologia e Química do mesmo órgão, para a pesquisa de Salmonella spp. e coliformes termotolerantes. Das 24 amostras, em 0/24 (0%) não foi constatada a presença de bactérias do gênero Salmonella spp. e 24/24 (100%) estavam contaminadas com coliformes termotolerantes, mas dentro dos valores estabelecidos na RDC nº 12/2001. Nas condições em que a pesquisa foi realizada e de acordo com os resultados encontrados, pode-se concluir que das 24 carcaças de frango comercializadas em estabelecimentos do Distrito sanitário V, cadastrados na Vigilância Sanitária do município, todas são próprias ao consumo, conforme estabelecido na RDC nº 12/2001 e RDC nº 13/2001.  
Pemanfaatan Saluran Irigasi Untuk Pembangkit Listrik Pikohidro Dengan Generator DC Shunt
Desa Kebumen Kabupaten Banyumas adalah salah satu desa yang terlewati Sungai Banjaran. Sungai ini menjadi salah satu sumber air untuk usaha pertanian dan perikanan, sehingga untuk mengalirkan air sungai ke persawahan dan kolam ikan dibuatlah saluran irigasi. Saluran irigasi di Desa Kebumen selalu mengalirkan air sepanjang waktu, walaupun pada musim kemarau. Potensi air irigasi ini merupakan sumber energi yang dapat dimanfaatkan untuk energi listrik. Penelitian ini merupakan rancang bangun sistem pembangkitan energi listrik dengan memanfaatkan tenaga air irigasi sebagai daya penggerak turbin undershot. Berdasarkan pengukuran aliran air pada saluran irigasi, saluran ini mempunyai debit sebesar 10.3 liter per detik, menghasilkan daya aktif sebesar 121,13 watt/detik. Dengan menggunakan turbin undershot berdiameter 60 cm, aliran air tersebut  dikonversikan menjadi daya putar mekanik sebesar 53.7 watt per detik. Daya putar mekanik tersebut kemudian diubah menjadi energi listrik oleh generator dc shunt sebesar 6.84 watt/detik. Generator ini mempunyai eksitasi sendiri dan menghasilkan listrik dc yang dapat disimpan dalam baterai. Efisiensi konversi turbin yang dapat dicapai adalah sebesar 44,33 % dan efisiensi konversi generator sebesar 12,74 %
Polymorphism of GSTM1 and GSTT1 genes in prostate cancer: A study from North India
BACKGROUND: Glutathione-S-transferases (GSTs) are active in the
detoxification of wide variety of endogenous or exogenous carcinogens.
The genetic polymorphisms of GSTM1 and GSTT1 genes have been studied
earlier to evaluate the relative risk of various cancers. AIM, SETTING
AND DESIGN: In the present study, we examined the association of the
GSTM1 and GSTT1 gene polymorphisms with sporadic prostate cancer
patients in north Indian population. MATERIAL AND METHODS: This case
control study was undertaken over a period of 24 months and included
103 prostate cancer patients and 117 controls; both patients and
controls originated from northern part of India. The GSTT1 and GSTM1
genotypes were identified by multiplex PCR in peripheral blood DNA
samples. STATISTICAL ANALYSIS: Difference in genotype prevalence and
association between case and control group were assessed by the Chi
square and Fisher Exact tests. RESULTS: Frequencies of null genotypes
in GSTT1 and GSTM1, was 11% (13/117) and 30% (35/117) respectively in
control individuals. The frequencies of GSTT1 and GSTM1 null genotypes
in prostate cancer patients were 34% (35/103) and 53% (55/103)
respectively. CONCLUSION: Our study demonstrates that the null
genotypes of GSTT1 and GSTM1 are substantially at higher risk for
prostate carcinoma as compared to the normal healthy controls. The
GSTT1 and GSTM1 null genotypes did not show significant association
with tobacco usage in prostate cancer patients. However, the null
genotypes were significantly stratified in 50-60 year-old patients when
incidence of prostate cancer is high
Changes in ponderal index and body mass index across childhood and their associations with fat mass and cardiovascular risk factors at age 15
Background: Little is known about whether associations between childhood adiposity and later adverse cardiovascular health outcomes are driven by tracking of overweight from childhood to adulthood and/or by vascular and metabolic changes from childhood overweight that persist into adulthood. Our objective is to characterise associations between trajectories of adiposity across childhood and a wide range of cardiovascular risk factors measured in adolescence, and explore the extent to which these are mediated by fat mass at age 15.
Methods and Findings: Using data from the Avon Longitudinal Study of Parents and Children, we estimated individual trajectories of ponderal index (PI) from 0-2 years and BMI from 2-10 years using random-effects linear spline models (N = 4601). We explored associations between PI/BMI trajectories and DXA-determined total-body fat-mass and cardiovascular risk factors at 15 years (systolic and diastolic blood pressure, fasting LDL-and HDL-cholesterol, triglycerides, C-reactive protein, glucose, insulin) with and without adjustment for confounders. Changes in PI/BMI during all periods of infancy and childhood were associated with greater DXA-determined fat-mass at age 15. BMI changes in childhood, but not PI changes from 0-2 years, were associated with most cardiovascular risk factors in adolescence; associations tended to be strongest for BMI changes in later childhood (ages 8.5-10), and were largely mediated by fat mass at age 15.
Conclusion: Changes in PI/BMI from 0-10 years were associated with greater fat-mass at age 15. Greater increases in BMI from age 8.5-10 years are most strongly associated with cardiovascular risk factors at age 15, with much of these associations mediated by fat-mass at this age. We found little evidence supporting previous reports that rapid PI changes in infancy are associated with future cardiovascular risk. This study suggests that associations between early overweight and subsequent adverse cardiovascular health are largely due to overweight children tending to remain overweight
Properties of Graphene: A Theoretical Perspective
In this review, we provide an in-depth description of the physics of
monolayer and bilayer graphene from a theorist's perspective. We discuss the
physical properties of graphene in an external magnetic field, reflecting the
chiral nature of the quasiparticles near the Dirac point with a Landau level at
zero energy. We address the unique integer quantum Hall effects, the role of
electron correlations, and the recent observation of the fractional quantum
Hall effect in the monolayer graphene. The quantum Hall effect in bilayer
graphene is fundamentally different from that of a monolayer, reflecting the
unique band structure of this system. The theory of transport in the absence of
an external magnetic field is discussed in detail, along with the role of
disorder studied in various theoretical models. We highlight the differences
and similarities between monolayer and bilayer graphene, and focus on
thermodynamic properties such as the compressibility, the plasmon spectra, the
weak localization correction, quantum Hall effect, and optical properties.
Confinement of electrons in graphene is nontrivial due to Klein tunneling. We
review various theoretical and experimental studies of quantum confined
structures made from graphene. The band structure of graphene nanoribbons and
the role of the sublattice symmetry, edge geometry and the size of the
nanoribbon on the electronic and magnetic properties are very active areas of
research, and a detailed review of these topics is presented. Also, the effects
of substrate interactions, adsorbed atoms, lattice defects and doping on the
band structure of finite-sized graphene systems are discussed. We also include
a brief description of graphane -- gapped material obtained from graphene by
attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic
Does the Order of Invasive Species Removal Matter? The Case of the Eagle and the Pig
Invasive species are recognized as a primary driver of native species endangerment and their removal is often a key component of a conservation strategy. Removing invasive species is not always a straightforward task, however, especially when they interact with other species in complex ways to negatively influence native species. Because unintended consequences may arise if all invasive species cannot be removed simultaneously, the order of their removal is of paramount importance to ecological restoration. In the mid-1990s, three subspecies of the island fox Urocyon littoralis were driven to near extinction on the northern California Channel Islands owing to heightened predation by golden eagles Aquila chrysaetos. Eagles were lured to the islands by an abundant supply of feral pigs Sus scrofa and through the process of apparent competition pigs indirectly facilitated the decline in foxes. As a consequence, both pigs and eagles had to be removed to recover the critically endangered fox. Complete removal of pigs was problematic: removing pigs first could force eagles to concentrate on the remaining foxes, increasing their probability of extinction. Removing eagles first was difficult: eagles are not easily captured and lethal removal was politically distasteful.Using prey remains collected from eagle nests both before and after the eradication of pigs, we show that one pair of eagles that eluded capture did indeed focus more on foxes. These results support the premise that if the threat of eagle predation had not been mitigated prior to pig removal, fox extinction would have been a more likely outcome.If complete eradication of all interacting invasive species is not possible, the order in which they are removed requires careful consideration. If overlooked, unexpected consequences may result that could impede restoration
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