Mathematical Modelling of flow in Schlemm's canal and its influence on primary open angle glaucoma

POAG (Primary Open Angle Glaucoma) is a major cause of blindness. This normally occurs when the IOP (intraocular pressure) increases. High pressure can be caused by an imbalance in the production and drainage of fluid (aqueous humour, AH) in the eye. AH is continually being produced but sometimes cannot be drained because of improperly functioning drainage channels (trabecular meshwork, TM). A mathematical model is presented for the flow of AH through the TM and into the SC (canal of Schlemm) and to couple this flow in order to predict changes in IOP. The governing equations have been developed by using the lubrication theory limit of the Navier-Stokes equations. To close the model, Friedenwald’s law has been used to predict changes of IOP. Several different cases have been examined in the model, relating AH flow to changes in IOP for various submodels: (i) the permeability, k in Darcy’s law may be either constant or not constant; (ii) the TM may be deformable so that the general theory of a beam under axial load is applicable - a number of different subcases where either ? or ?, may be either large or small have been considered. However only the subcase ? is small has been discussed in this study by assuming the permeability, k is constant and the TM is deformable. This subcase has been solved by using the regular perturbation method. The results show that the IOP rises continually when ? is small and may cause blindness

Elasticity of nanometer-sized objects

We initiate the development of a theory of the elasticity of nanoscale objects based upon new physical concepts which remain properly defined on the nanoscale. This theory provides a powerful way of understanding nanoscale elasticity in terms of local group contributions and gives insight into the breakdown of standard continuum relations. We also give two applications. In the first, we show how to use the theory to derive a new relation between the bending and stretching properties of nanomechanical resonators and to prove that it is much more accurate than the continuum-based relations currently employed in present experimental analyses. In the second, we use the new approach to link features of the underlining electronic structure to the elastic response of a silicon nanoresonator.Comment: 11 pages, 5 figure

The correlation energy functional within the GW-RPA approximation: exact forms, approximate forms and challenges

In principle, the Luttinger-Ward Green's function formalism allows one to compute simultaneously the total energy and the quasiparticle band structure of a many-body electronic system from first principles. We present approximate and exact expressions for the correlation energy within the GW-RPA approximation that are more amenable to computation and allow for developing efficient approximations to the self-energy operator and correlation energy. The exact form is a sum over differences between plasmon and interband energies. The approximate forms are based on summing over screened interband transitions. We also demonstrate that blind extremization of such functionals leads to unphysical results: imposing physical constraints on the allowed solutions (Green's functions) is necessary. Finally, we present some relevant numerical results for atomic systems.Comment: 3 figures and 3 tables, under review at Physical Review

Anomaly-induced Quadrupole Moment of the Neutron in Magnetic Field

The neutrons cannot possess a quadrupole moment in the vacuum. Nevertheless, we show that in the presence of an external magnetic field the neutrons acquire a new type of quadrupole moment $Q^{ij}= \chi\,\sigma^i B^j$ involving the components of spin and magnetic field. This "chiral magnetic" quadrupole moment arises from the interplay of the chiral anomaly and the magnetic field; we estimate its value for the neutron in the static limit, and find $\chi \simeq 1.35\cdot10^{-2}\,{\rm fm}^4$. The detection of the quadrupole moment of the neutron would provide a novel test of the role of the chiral anomaly in low-energy QCD and can be possible in the presence of both magnetic and inhomogeneous electric fields. The quadrupole moment of the neutron may affect e.g. the properties of neutron stars and magnetars.Comment: 2 pages; extended versio

Period doubling in glow discharges: local versus global differential conductivity

Short planar glow discharges coupled to a resistive layer exhibit a wealth of spontaneous spatio-temporal patterns. Several authors have suggested effective reaction-diffusion-models to explore similarities with other pattern forming systems. To test these effective models, we here investigate the temporal oscillations of a glow discharge layer coupled to a linear resistor. We find an unexpected cascade of period doubling events. This shows that the inner structure of the discharge is more complex than can be described by a reaction-diffusion-model with negative differential conductivity.Comment: 4 pages, 4 figures, submitted to PR

Diameter and Chirality Dependence of Exciton Properties in Carbon Nanotubes

We calculate the diameter and chirality dependences of the binding energies, sizes, and bright-dark splittings of excitons in semiconducting single-wall carbon nanotubes (SWNTs). Using results and insights from {\it ab initio} calculations, we employ a symmetry-based, variational method based on the effective-mass and envelope-function approximations using tight-binding wavefunctions. Binding energies and spatial extents show a leading dependence with diameter as $1/d$ and $d$, respectively, with chirality corrections providing a spread of roughly 20% with a strong family behavior. Bright-dark exciton splittings show a $1/d^2$ leading dependence. We provide analytical expressions for the binding energies, sizes, and splittings that should be useful to guide future experiments

Radiographic Study of Developmental Alteration in Tooth Number Among Children in IIUM Dental Clinic

Background: The aim of this research was to determine the prevalence, distribution and association of developmental alteration in tooth number with gender, location, and presence of delayed eruption of tooth among children who attended to Student's polyclinic of IIUM Kuantan, Malaysia. Methods: A cross sectional study on total 727 Orthopanthomograms (OPGs) of 3-17 years old children from April 2009 to July 2012. OPGs with presence of alteration number were scrutinized to find out the prevalence, distribution and association. The data was analyzed comparing gender, location and presence of delayed eruption and tested using Chi-square test. Results: Out of 727 OPGs, 71 OPGs showed developmental alteration in tooth number. The prevalence was 98/1000 OPGs within 3 years. Among those 71 OPGs, the gender differences were: males (49.3%) and females (50.7%). Locations were found in maxilla (45.1%), mandible (40.8%) and both (14.0%). The finding of delayed eruption was (7.0%). There were significant differences between alteration in tooth number with location as (p<0.05) while there were no significant differences with gender and delayed eruption as (p>0.05). Conclusions: This study showed that hyperdontia was considerably lower than hypodontia. There was association between alteration in tooth number with location, but no association with gender and delayed eruption

Analisis Tingkat Kesejahteraan Rumah Tangga Nelayan Mini Purse Seine Dengan Fishing Basedi Ppp Tasik Agung Kabupaten Rembang Jawa Tengah

Penelitian ini bertujuan untuk menganalisis tingkat kesejahteraan nelayan juragan dan ABK mini purse seine di PPP Tasik Agung Kabupaten Rembang, Jawa Tengah.Metode yang digunakan adalah metode deskriptif yang bersifat survei. Teknik pengambilan sampel menggunakan metode purposive sampling. Teknik pengumpulan data dilakukan dengan metode wawancara mendalam yang dilengkapi daftar kuisioner dan juga observasi langsung di lapangan. Teknik analisis data menggunakan 12 indikator kemiskinan gabungan yang terdiri dari indikator kemiskinan menurut Badan Pusat Statistik Pusat (2007), Badan Pusat Statistik Pusat 2006), indikator kemiskinan menurut Pridaningsih (2011), indikator kemiskinan menurut Safitri (2011), serta konsep Nilai Tukar Nelayan (NTN). Hasil penelitian menunjukkan bahwa tingkat kesejahteraan nelayan yang dianalisis menggunakan 12 indikator kemiskinan gabungan menunjukkan bahwa nelayan termasuk ke dalam kriteria tidak miskin atau tergolong sejahtera. Sedangkan hasil analisis tingkat kesejahteraan nelayan berdasarkan NTN juragan sebesar 1,67 (NTN > 1) dan NTN ABK sebesar 1,44 (NTN >1) yang menunjukkan bahwa nelayan juragan dan ABK termasuk dalam kriteria tidak miskin/sejahtera. Hasil uji z,nilai z hitung = 0,445 < 1.985= z tabel, dan sig = 0,657 >5% menunjukkan bahwa tidak ada perbedaan metode antara NTN dengan Indikator Kemiskinan Gabungan yang mempengaruhi tingkat kesejahteraan nelayan secara signifikan. The purpose of this research was to analyze prosperity level of Employer and Crew Mini Purse Seine Fisheries in Tasik Agung Fishing Port of Rembang Regency Central Java. The method used is descriptive method by survey. The sampling technique used purposive sampling method. Data was collected by depth interview method that include a list of questionnaires and direct observation in the field. The collection data was carried out by combination of 12 poverty indicators, consisted of poverty indicator according to The Statistical Corporation (2007), The Statistical Corporation (2006), modification poverty indicator according to Pridaningsih (2011), modification poverty indicator according Safitri (2011), and a Fishery Term of Trade Index (NTN) concept. The result of the analysis using combination of 12 poverty indicators have shown that those fisherman were not poor or prosperous. Meanwhile, the analysis employer' NTN = 1,67 (NTN > 1) and crew' NTN = 1,44(NTN > 1) that mean both of them were not poor or prosperous. Test results z, the value of z = 0.445 <1.985 = z table, and sig = 0.657> 5% indicates that there is no difference between the method NTN Combined with Poverty Indicators affecting significantly the welfare of fishermen