Switchable metamaterial reflector/absorber for different polarized electromagnetic waves

We demonstrate a controllable electromagnetic wave reflector/absorber for different polarizations with metamaterial involving electromagnetic resonant structures coupled with diodes. Through biasing at different voltages to turn ON and OFF the diodes, we are able to switch the structure between nearly total reflection and total absorption of a particularly polarized incident wave. By arranging orthogonally orientated resonant cells, the metamaterial can react to different polarized waves by selectively biasing the corresponding diodes. Both numerical simulations and microwave measurements have verified the performance.Comment: 11 pages, 4 figure

Evaluation of false positivity and cross reactivity in the investigation of Human Immunodeficiency Virus (HIV) antibodies

This study evaluated the causes of false positive Human Immunodeficiency Virus test results (F+HIV), cross reactivity of HIV antibodies with other non HIV antibodies, and efficiency of the serial and parallel testing algorithms. 100 blood samples randomly collected from clients attending the Heart to Heart HIV counseling and testing unit of FMC Umuahia, were screened using the rapid ELISA and Enzyme Immuno Assay (EIA) tests. Discordant HIV results were screened for Anti Streptolycin O (ASO), Rheumatoid factor (RF) and Hepatitis B surface antigen (HBsAg). Of the 100 samples, 73 were negative to HIV antibodies, 11 positive, and 16 discordant results. EIA confirmed 8 of 16 discordant results negative, 5 indeterminate and 3 positive. F+ results were 33%, and false negatives were 4%. A marked percentage of samples exhibited cross reactivity with ASO (8;62%), HBsAg(3;23%), and RF (2;15%). An Odds Ratio (OR) of 33:0 (95% CI  13.8-26.2), showed that Determine rapid test kit is 33 times more likely to give a false positive HIV result than Unigold rapid test kit. The parallel algorithm showed better efficiency than the serial. This study showed that F+HIV test result is prevalent, and cross reactivity is the plausible cause of F+HIV test results.Keywords: Cross- reactivity, false positive, HIV, Umuahia

QCD Factorization Based on Six-Quark Operator Effective Hamiltonian from Perturbative QCD and Charmless Bottom Meson Decays B(s)→ππ,πK,KKB_{(s)}\to \pi\pi,\pi K, KK

The charmless bottom meson decays are systematically investigated based on an approximate six quark operator effective Hamiltonian from perturbative QCD. It is shown that within this framework the naive QCD factorization method provides a simple way to evaluate the hadronic matrix elements of two body mesonic decays. The singularities caused by on mass-shell quark propagator and gluon exchanging interaction are appropriately treated. Such a simple framework allows us to make theoretical predictions for the decay amplitudes with reasonable input parameters. The resulting theoretical predictions for all the branching ratios and CP asymmetries in the charmless $B^0, B^+, B_s\to \pi\pi, \pi K, KK$ decays are found to be consistent with the current experimental data except for a few decay modes. The observed large branching ratio in $B\to \pi^0\pi^0$ decay remains a puzzle though the predicted branching ratio may be significantly improved by considering the large vertex corrections in the effective Wilson coefficients. More precise measurements of charmless bottom meson decays, especially on CP-violations in $B\to K K$ and $B_s\to \pi\pi, \pi K, KK$ decay modes, will provide a useful test and guide us to a better understanding on perturbative and nonperturbative QCD.Comment: 36 pages, 5 figures, typos correcte

Agroeconomic evaluation of black Sigatoka resistant hybrid plantains under smallholder management systems

Plantain production in Sub-Saharan Africa has been seriously threatened by black Sigatoka disease since the early 1980s. The International Institute of Tropical Agriculture has succeeded in developing hybrids that are resistant to the disease, and out-yields the best landrace by about 100%. Beforeintroducing these hybrids to the farmers, their performance at the smallholder environment has to be established. This study was carried out to assess the performance of the hybrids under farmermanagedsystems, using PITA14 (a hybrid) and Agbagba (best landrace). Thirty-six farmers from nine villages were involved. Five suckers each of the varieties were planted in farmers' fields. Data were collected over a period of 22 months on the agronomy, economics, post harvest and marketing. Resultsshow that PITA14 had reduced cropping cycle compared to the landrace. Average black Sigatoka resistant index was 96% for PITA14 against Agbagba’s 48%. The mean bunch weight was 13.3kg for PITA14 and 7.0Kg for Agbagba. Eighty-three percent of the farmers harvested 124 bunches from 81 mats of PITA14, while 55% harvested 62 bunches from 52 mats of Agbagba. Each farmer obtained an equivalent of $8.62 from PITA14 and$4.33 from Agbagba. The post harvest technology attributes wereranked higher for the hybrid. The combination of disease resistance and increased yield by the hybrid is suggestive of its high adoption potential

Cross-Dataset Person Re-Identification via Unsupervised Pose Disentanglement and Adaptation

Person re-identification (re-ID) aims at recognizing the same person from images taken across different cameras. To address this challenging task, existing re-ID models typically rely on a large amount of labeled training data, which is not practical for real-world applications. To alleviate this limitation, researchers now targets at cross-dataset re-ID which focuses on generalizing the discriminative ability to the unlabeled target domain when given a labeled source domain dataset. To achieve this goal, our proposed Pose Disentanglement and Adaptation Network (PDA-Net) aims at learning deep image representation with pose and domain information properly disentangled. With the learned cross-domain pose invariant feature space, our proposed PDA-Net is able to perform pose disentanglement across domains without supervision in identities, and the resulting features can be applied to cross-dataset re-ID. Both of our qualitative and quantitative results on two benchmark datasets confirm the effectiveness of our approach and its superiority over the state-of-the-art cross-dataset Re-ID approaches.Comment: Accepted to ICCV 201

A Retrospective Study of Rabies Cases Reported at Vom Christian Hospital, Plateau State, Nigeria, 2006 – 2010

Rabies is a zoonosis of public health importance in Nigeria. Exposure to bites of rabid dogs is the cause of over 99% of human cases of rabies worldwide. Post-Exposure Prophylaxis (PEP) is a vital aspect of clinical rabies prevention in humans The aim of this study was to determine the magnitude of rabies disclosure among dogbite victims (DBVs) and their compliance with a PEP regimen. We reviewed patient records of DBVs who were treated at the Vom Christian Hospital, Plateau State, from 2006 – 2010, obtained information on patient demographics and rabies status of implicated dogs from patients' hospital records. A trend of reported rabid dog bites in children was determined. We assessed compliance of DBVs with the recommended dosage regimen for PEP which is local wound treatment followed by vaccine therapy on days 0, 3, 7, 14 and 30. Over the five-year period, 713 DBVs were reported; 377(52.9%) were children <15 years, 404(56.7%) were males and 299 (41.9%) were bitten by laboratory-confirmed rabid dogs.Rabid dog-bites among children increased exponentially from 2007(6/1,000,000) to 2009(41/1,000,000) with a steep decline in 2010 (24/1,000,000). Of all DBVs, 677 (95%) first sought veterinary care. Of all implicated dogs, 305(42.8%) were tested and 299 (98.0%) were positive for rabies. Nearly all (99.6%) DBVs were treated using human diploidcell rabies vaccine, while only 49.1% completed the recommended doses. Of the 299 DBVs bitten by rabies-positive dogs, 59.2% completed the regimen and were likely to be PEP compliant than those bitten by untested dogs (p<0.01). No mortalities among DBVs were reported to the hospital. Rabies in dogs is a serious public health problem in Plateau State, in which children constitute the highest proportion of rabid DBVs reported. We recommend joint sensitization of physicians and veterinarians about the need for detailed DBV and animal information for rabies management.Keywords: Rabies, Dog bite victims, Post Exposure Prophylaxis, NigeriaNigerian Veterinary Journal, VOL:32 (4) 366-37

An Updated Search of Steady TeV γ−\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV $\gamma-$ray point sources has now been updated by a factor of 2.8 improved statistics. From $0.0^{\circ}$ to $60.0^{\circ}$ in declination (Dec) range, no new TeV $\gamma-$ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV $\gamma-$ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn

Can plastid genome sequencing be used for species identification in the Lauraceae?

Using DNA barcoding for species identification remains challenging for many plant groups. New sequencing approaches such as complete plastid genome sequencing may provide some increased power and practical benefits for species identification beyond standard plant DNA barcodes. We undertook a case study comparing standard DNA barcoding to plastid genome sequencing for species discrimination in the ecologically and economically important family Lauraceae, using 191 plastid genomes for 131 species from 25 genera, representing the largest plastome data set for Lauraceae to date. We found that the plastome sequences were useful in correcting some identification errors and for finding new and cryptic species. However, plastome data overall were only able to discriminate c. 60% of the species in our sample, with this representing a modest improvement from 40 to 50% discrimination success with the standard plant DNA barcodes. Beyond species discrimination, the plastid genome sequences revealed complex relationships in the family, with 12/25 genera being non-monophyletic and with extensive incongruence relative to nuclear ribosomal DNA. These results highlight that although useful for improving phylogenetic resolution in the family and providing some species-level insights, plastome sequences only partially improve species discrimination, and this reinforces the need for large-scale nuclear data to improve discrimination among closely related species

“Lossless” compression of high resolution mass spectra of small molecules

Fourier transform ion cyclotron resonance (FTICR) provides the highest resolving power of any commercially available mass spectrometer. This advantage is most significant for species of low mass-to-charge ratio (m/z), such as metabolites. Unfortunately, FTICR spectra contain a very large number of data points, most of which are noise. This is most pronounced at the low m/z end of spectra, where data point density is the highest but peak density low. We therefore developed a filter that offers lossless compression of FTICR mass spectra from singly charged metabolites. The filter relies on the high resolving power and mass measurement precision of FTICR and removes only those m/z channels that cannot contain signal from singly charged organic species. The resulting pseudospectra still contain the same signal as the original spectra but less uninformative background. The filter does not affect the outcome of standard downstream chemometric analysis methods, such as principal component analysis, but use of the filter significantly reduces memory requirements and CPU time for such analyses. We demonstrate the utility of the filter for urinary metabolite profiling using direct infusion electrospray ionization and a 15 tesla FTICR mass spectrometer

Charmless Bs→PP,PV,VVB_s\to PP, PV, VV Decays Based on the six-quark Effective Hamiltonian with Strong Phase Effects II

We provide a systematic study of charmless $B_s \to PP, PV, VV$ decays ($P$ and $V$ denote pseudoscalar and vector mesons, respectively) based on an approximate six-quark operator effective Hamiltonian from QCD. The calculation of the relevant hard-scattering kernels is carried out, the resulting transition form factors are consistent with the results of QCD sum rule calculations. By taking into account important classes of power corrections involving "chirally-enhanced" terms and the vertex corrections as well as weak annihilation contributions with non-trivial strong phase, we present predictions for the branching ratios and CP asymmetries of $B_s$ decays into PP, PV and VV final states, and also for the corresponding polarization observables in VV final states. It is found that the weak annihilation contributions with non-trivial strong phase have remarkable effects on the observables in the color-suppressed and penguin-dominated decay modes. In addition, we discuss the SU(3) flavor symmetry and show that the symmetry relations are generally respected