169 research outputs found
Surveillance for familial and hereditary pancreatic ductal adenocarcinoma
Pancreatic ductal adenocarcinoma is one of the most lethal forms of cancer. This book describes the outcome of long-term surveillance for p16-Leiden/CDKN2A mutation carriers. Further evaluating the role of precursor lesions, including IPMN and PanIN in the development of PDAC. It is also common knowledge that hereditary cancer is associated with the development of multiple tumors due to the fact that all body cells carry the inherited mutation. Therefore the third aid was to evaluate the risk of multiple PDAC in carriers of a p16-Leiden founder mutation. The fourth aim was to evaluate cost-effectiveness of surveillance. During our surveillance study, the program unexpectedly detected also other types of cancer than PDAC including benign lesions (incidentaloma). The fifth aim was to evaluate what type of cancers and benging lesions were detected and whether surveillance and early detection offered any benefit. The final aim was to describe the dilemmas in the management of screen-detected lesions that we experienced during our surveillance program. Universiteit Leiden;
HIX;
ABN AmroLUMC / Geneeskund
Extent of Extension Service Delivery for Agro-pastoralists in Niger State,Nigeria
The study examines the extent of agricultural extension services deleivery to agro-pastoralists in Niger State. Nigeria. Primary data were collected through field survey from agropastorialist from three purposely selected Local Government Areas in Niger State. Katcha, Paiko and Wushishi LGA’s were purposely selected by making sure they were in different agricultural zones of the Niger State namely Zone I, II and III respectively. Twenty percent of the agropastoralists house-hold population was sampled from each of three LGA randomly. A total of 210 household heads were sampled and interviewed using a semi structured survey instrument administered by trained enumerators who understood the local language. Both descriptive and inferential statistics were employed to analyse the data. Results revealed that all (100%) of the household heads were all males and 67.7% acquired adult education while agro-pastoralism was the major occupation (98.1%). Majority (98.1%) of the agro-pastoralists claimed they were of Fulani ethnic group. Information on out break of diseases (mean=3.9); provision of grazing reserves (mean=3.7) were reported high. Majority (99.5%) of the respondents opined that lack of easy access to vaccines and non- proximity of veterinary clinic were major constraints. In the testing of hypotheses, Pearson Product Moment Correlation (PPMC) showed a significant positive relationship between extent of extension service provision and the following variables namely Age (r =0.172; p<0.05), number of wives (r =0.163; p<0.05), number of children (r =0.222 and; p<0.05), and number of cows owned (r =0.221; p<0.05). The result of Chi-square analysis shows that there was a significant relationship between Extent of extension provision and the settlement type (X2 =10.21; p<0.05), Extent of extension provision and educational level (X2 =12.20;p<0.05). It was recommended that government should make adequate arrangement for provision of neccessary infra-structure in the already gazzeted grazing reserve most especially vetinery clinics and make vaccine available and affordable for them. There is need to produce more radio programmes and also encourage formation of radio listening group since is one of the major source of information to their production system. Keywords: Agriculture, Extension service delivery, agropastoralist
The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)
-During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement
The Effect of Strain Rate on Electrical and Mechanical Characteristics of Pure Aluminum Using Equal Channel Angular Pressing (ECAP)
-During equal-channel angular pressing (ECAP), the effect of severe plastic deformation (SPD) rate on both the electrical (electrical resistance, denoted as (R),Ω and The electrical resistivity denoted as (ρ), Ω.m) and mechanical characteristics (Ultimate Tensile Strength abbreviated as (UTS), MPa and Micro-Hardness measured in Vickers Hardness Number, abbreviated as VHN) of pure aluminum alloy are experimentally investigated.ECAP was used to improve the pure aluminum alloy\u27s microstructure at room temperature, which had samples with square cross sections. The findings indicate that as the rate of strain decreases from 0.3 to 0.1 s^-1, there is a gradual increase in both Ultimate Tensile Strength (UTS) and hardness, with the highest values observed at a strain rate of 0.025 s^-1.This study empirically explored the influence of ECAP on the macrostructure, microstructure, mechanical properties, and electrical properties of pure aluminum alloy at different strain rates (s^-1) – 0, 0.025, 0.1, and 0.3. In summary, it was observed that under the optimized ECAP conditions, specifically at a strain rate of 0.025 s^-1, the ultimate tensile strength increased by approximately 266%, micro-hardness by about 210%, and electrical resistivity by roughly 250% compared to the base material. The maximum value of the ultimate tensile strength was equal to 93 MPa, while the maximum value of hardness was equal to 41 VNN, and the maximum value of electrical resistivity was equal to 1.8 Ω.m, which is equivalent to the ratios mentioned above. Additionally, there was notable fragmentation of course second-phase particles and microstructure refinement
Evaluation of the impact of Acacia nilotica and Annona senegalensis as potential sources of phytogenic compounds on performances of commercial broiler chickens
The study investigated the impact of Acacia nilotica and Annona senegalensis leaves, as potential sources of phytogenics in broiler diets through a completely randomized design experiment. For both plants, chickens in control were fed diets without phytogenic sources, while the chicken in the test groups T2, T3, and T4, were fed with diets containing 200 g leaves per kg of feed, 200 g seed (ANS) per kg of feed, and 100 g each of both leaves and seeds per kg of feed, respectively. Performance parameters including body weight, feed intake, weight gain, feed conversion ratio was recorded while haematological parameters including white blood cells, haematocrit, platelets, haemoglobin, and red blood cells of the chickens were assessed at the end of the study. The results showed that broilers fed diet containing both Acacia nilotica leaves and seeds (T4) had the highest body weight at 8 weeks (5011.10g, p<0.05), total feed intake (4100.00g, p<0.05), weight gain (4298.70g, p<0.05), and the most efficient feed-to-gain ratio (0.95, p<0.05). The broiler chickens fed diets containing Annona senegalensis leaves and seeds showed no significant differences in final body weight or weight gain compared to the control group (p = 0.414), with T3 having the highest average final body weight (3480g). However, feed intake patterns varied significantly, with T2 having the lowest average feed intake (2993g, p<0.05), and the control group having the highest feed intake, while no significant differences were observed in feed conversion ratios (FCR) among all groups, indicating similar feed efficiency across diets. Supplementation with Acacia nilotica leaves and seeds significantly increased white blood cell counts (p<0.05) in broiler chickens, with T2, T3, and T4 showing higher values (98.78 x 106/μL, 101.08 x 106/μL, and 101.24 x 106/μL, respectively) compared to control (82.98 x 106/μL). Conversely, Annona senegalensis leaves and seeds did not significantly affect white blood cell counts or other haematological parameters (p>0.05). This study demonstrates the potential of Acacia nilotica and Annona senegalensis as promising phytogenic alternatives for enhancing broiler chicken performance. However further research is warranted to explore the specific bioactive compounds in the test ingredients for these effects and optimize their use in poultry diets for sustainable and productive poultry production
Dephasing time of disordered two-dimensional electron gas in modulated magnetic fields
The dephasing time of disordered two-dimensional electron gas in a modulated
magnetic field is studied. It is shown that in the weak inhomogeneity limit,
the dephasing rate is proportional to the field amplitude, while in strong
inhomogeneity limit the dependence is quadratic. It is demonstrated that the
origin of the dependence of dephasing time on field amplitude lies in the
nature of corresponding single-particle motion. A semiclassical Monte Carlo
algorithm is developed to study the dephasing time, which is of qualitative
nature but efficient in uncovering the dependence of dephasing time on field
amplitude for arbitrarily complicated magnetic-field modulation. Computer
simulations support analytical results. The crossover from linear to quadratic
dependence is then generalized to the situation with magnetic field modulated
periodically in one direction with zero mean, and it is argued that this
crossover can be expected for a large class of modulated magnetic fields.Comment: 8 pages, 2 figure
Rainfall-induced hydraulic properties for unsaturated soil in Klang valley
Klang Valley area is one of the most landslide-prone areas in Malaysia, especially at
Hulu Kelang, Kuala Lumpur. The area has been frequently hit by landslide since 1990s. Soil
instability is agreed by researchers occurred due to high precipitation and long duration of
rainfall which cause property damage and leading to injury and fatality. Slope failure is also
triggered by the antecedent rainfall leads to infiltration of rainwater into soil. Therefore, study
of rainwater infiltration is vital to relates soil – water interaction and soil behaviour for varies
of rainfall intensities and duration for unsaturated soil. The objective of this paper is to
determine and compare soil water characteristic curve (SWCC) which is one of the soil
hydraulic parameters for Klang Valley area. Samples were collected to determine the soil
hydraulic properties at Hulu Kelang area, Universiti Kebangsaan Malaysia (UKM) and
Universiti Pertahanan Nasional Malaysia (UPNM) campuses. SWCC was obtained by pressure
plate extractor apparatus experiment and the analysis was performed using Van Genuchten
equation. Result of parameters obtained shows significant differences of soil at Hulu Kelang
area compared to soils at UKM and UPNM campuses. This research is relevant to supports
national slope master plan 2009-2023
Self-similarity and novel sample-length-dependence of conductance in quasiperiodic lateral magnetic superlattices
We study the transport of electrons in a Fibonacci magnetic superlattice
produced on a two-dimensional electron gas modulated by parallel magnetic field
stripes arranged in a Fibonacci sequence. Both the transmission coefficient and
conductance exhibit self-similarity and the six-circle property. The presence
of extended states yields a finite conductivity at infinite length, that may be
detected as an abrupt change in the conductance as the Fermi energy is varied,
much as a metal-insulator transition. This is a unique feature of transport in
this new kind of structure, arising from its inherent two-dimensional nature.Comment: 9 pages, 5 figures, revtex, important revisions made. to be published
in Phys. Rev.
CP violation in chargino decays in the MSSM
In the minimal supersymmetric standard model (MSSM) with complex parameters,
supersymmetric loop effects can lead to \emph{CP} violation. We calculate the
rate asymmetries of decays of charginos into the lightest neutralino and a
boson on the basis of the most important loop contributions in the third
generation squark sectors. It turns out that the \emph{CP} violating
asymmetries can be a few per cent in typical regions of the parameter space of
the MSSM. These processes would provide very promising channels for probing
\emph{CP} violation in the MSSM at future high-energy colliders.Comment: 15 pages, 5 figures, LaTeX2
Tunable Lyapunov exponent in inverse magnetic billiards
The stability properties of the classical trajectories of charged particles
are investigated in a two dimensional stadium-shaped inverse magnetic domain,
where the magnetic field is zero inside the stadium domain and constant
outside. In the case of infinite magnetic field the dynamics of the system is
the same as in the Bunimovich billiard, i.e., ergodic and mixing. However, for
weaker magnetic fields the phase space becomes mixed and the chaotic part
gradually shrinks. The numerical measurements of the Lyapunov exponent
(performed with a novel method) and the integrable/chaotic phase space volume
ratio show that both quantities can be smoothly tuned by varying the external
magnetic field. A possible experimental realization of the arrangement is also
discussed.Comment: 4 pages, 6 figure
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