Nanoscale magnetometry using a single spin system in diamond

We propose a protocol to estimate magnetic fields using a single nitrogen-vacancy (N-V) center in diamond, where the estimate precision scales inversely with time, ~1/T$, rather than the square-root of time. The method is based on converting the task of magnetometry into phase estimation, performing quantum phase estimation on a single N-V nuclear spin using either adaptive or nonadaptive feedback control, and the recently demonstrated capability to perform single-shot readout within the N-V [P. Neumann et. al., Science 329, 542 (2010)]. We present numerical simulations to show that our method provides an estimate whose precision scales close to ~1/T (T is the total estimation time), and moreover will give an unambiguous estimate of the static magnetic field experienced by the N-V. By combining this protocol with recent proposals for scanning magnetometry using an N-V, our protocol will provide a significant decrease in signal acquisition time while providing an unambiguous spatial map of the magnetic field.Comment: 8 pages and 5 figure

Performance comparison of differential space-time signalling schemes for OFDM systems

Differential transmit diversity is an attractive alternative to its coherent counterpart, especially for multiple antenna systems where channel estimation is more difficult to attain compared to that of single antenna systems. In this paper we compare two different types of differential transmit diversity techniques for OFDM based transmissions. The first technique uses differential space-time block codes (DSTBC) from orthogonal designs and the second uses the differential cyclic delay diversity (DCDD). The results compare the bit error performance for several transmit antenna configurations. The results show that DCDD offers a very close performance to that of DSTBC, with the advantage of a simplified receiver structure

Enhanced controlling of the SLS Process during a build

Current commercial Rapid Prototyping (RP) systems like Stereolithography (3D Systems Corporation) and Selective Laser Sintering (DTM Corporation) use galvanometers from General Scanning Inc. (GSI) for the positioning of the laser beam. The GSI scanners are delivered as a ''black box". Operating Consoles which are usually Personal Computers (PC) have very few feedback from the performance of the GSI scanners. Therefore, the PC spends 9000 or more of its time waiting for the GSI scanners to be over with the building of the current layer before sending the information regarding the next layer. Also, very little process control can be performed during the scanning of a layer using the GSI scanners. This kind of setup prevents any dynamic controlling of the process that could prevent building errors like burning, warping etc. At Clemson University, our team has developed both hardware and software components that allows a dynamic control of the building process. New features like scanning one vector with laser power as a function of position and/or time are now possible. Both hardware and software issues will be presented.Mechanical Engineerin

Immune Dysfunction and Antiretroviral Therapy Challenges in Children and Adolescents Living with Human Immunodeficiency Virus

Human immunodeficiency virus (HIV) infection results in progressive decline in immune function ultimately leading to acquired immunodeficiency syndrome (AIDS) characterised by increased susceptibility to opportunistic infections and malignancies. In addition, it causes immune dysfunction, which manifests as a persistent inflammatory state due to dysregulation of cytokine production. Antiretroviral therapy (ART) not only improves immune function but also mitigates systemic immune activation associated with disease progression. Early initiation of ART in children living with HIV has led to a growing cohort surviving into adolescence and beyond. As such, they will experience lifelong exposure to an array of physiologic processes associated with systemic infection, immune dysfunction and antiretroviral medications. This leaves them not only susceptible to a range of morbidities associated with chronic inflammation, immune dysregulation, and drug toxicity but also vulnerable to treatment fatigue leading to issues with treatment adherence and engagement in care. Children experience additional barriers to maintaining suppressive ART due to limited paediatric-friendly formulations that are palatable and contribute to regimen complexity. Tolerability and durability of long-term ART are integral in optimising outcomes for children and adolescents living with HIV and maximising viability of future ART regimens throughout adulthood

Penerapan Metode Simple Additive Weighting Dalam Sistem Pendukung Keputusan Kelayakan Laboratorium Komputer SMP Dan SMA Negeri Untuk Unit Pelaksana Teknis Dinas Pendidikan Kecamatan Sukorejo

— Perluasan pemanfaatan komputer yang semula dimanfaatkan sedikit orang, kini menjadi dimanfaatkan banyak orang. Hal ini mengakibatkan Perubahan pada berbagai bidang kehidupan seperti halnya dalam proses pengambilan sebuah keputusan, terkadang keputusan yang dibuat oleh seseorang atau sekelompok secara manual kurang akurat dalam penilaiannya, seperti instansi pemerintahan UPTD Pendidikan Kecamatan Sukorejo dalam mengambil sebuah keputusan menentukan kelayakan laboratorium komputer sekolah. Tujuan dari penelitian ini adalah Untuk membangun sebuah sistem pendukung keputusan dalam menentukan kelayakan laboratorium komputer SMP dan SMA Negeri se Kecamatan Sukorejo menggunakan metode Simple Additive Weighting. Metode pengembangan sistem yang digunakan adalah model sekuensial linier, atau biasa disebut model air terjun (waterfall), metode ini merupakan salah satu model pengembangan berbasis SDLC (System Development Life Cycle). Hasil penelitian dengan pengujian sistem oleh 3 orang ahli dengan hasil 88,67% (Sangat Setuju), 2 orang admin dengan hasil 90% (Sangat Setuju), 2 orang pengunjung dengan hasil 86,23% (Sangat Setuju), dan pengujian blackbox yang semua hasilnya adalah valid. Setelah sistem ini digunakan untuk memberi keputusan kelayakan laboraorium komputer enam sekolah, hasil dari keenam sekolah tersebut adalah layak. Hasil dari kelayakan laboratorium tersebut untuk laporan kepada pemerintah tentang perkembangan laboratorium komputer. Berdasarkan penelitian yang telah dilakukan diperoleh simpulan bahwa sistem ini layak digunakan dan memberikan kemudahan bagi staf ahli sarana dan prasarana UPTD Pendidikan dalam menentukan kelayakan laboratorium komputer dibandingkan dengan cara manual.Kata kunci— UPTD, Waterfall, Simple Additive Weightin

Learning Motivation increased due to a Relaxed Assessment in a Competitivee-Learning Environment

In this work, e-learning is used to increase learners 'motivation and competence in addition to learning complementary environment. This work is based on of the 7-years of hybrid e-learning classes on Operating System, Computer Network, Network Security, Network Management subjects at 3 Indonesian universities, namely, Surya University, STKIP Surya, and IBI Darmajaya. Most of STKIP Surya's students are from Papua and need more attention and motivation than others. Relaxed assessment processes are performed on each module in addition to mid term and final exams. On average, there are 12-18 modules in each subject matter. To motivate the learners, they may perform as many exams as ones' wish to attained the highest possible mark within the semester on all exams and quizzes. Relaxed assessment processes to attained maximum grades seems to increase the learners' motivation as some learners' retrying in exceeding 50 times for the 100 questions final shown in the Level of Competency (LoC) measurement. In addition, to anticipate, any cheating, eliminate remedial and cost savings, all exams are done on moodle via web. Such method of a whole semester relaxed assessment equipped with about 2000-6000 questions bank per subject and is for the first time performed in Indonesia. This study is also found an increase in the majority of learner's understanding on the subject is very good without remedial. Thus, e-learning seems not only complement learning processes but also able to motivate and to improve the competence of learners as well creating healthy competitive environment among learners

Vitamin D Status and TB Treatment Outcomes in Adult Patients in Tanzania: A Cohort Study.

Vitamin D is an immunomodulator and can alter response to tuberculosis (TB) treatment, though randomised trials have been inconclusive to date. We present one of the first comprehensive analysis of the associations between vitamin D status and TB treatment, T-cell counts and nutritional outcomes by HIV status. Cohort study. Outpatient clinics in Tanzania. 25-hydroxyvitamin D levels were assessed in a cohort of 677 patients with TB (344 HIV infected) initiating anti-TB treatment at enrolment in a multivitamin supplementation (excluding vitamin D) trial (Clinicaltrials.gov identifier: NCT00197704). Information on treatment outcomes such as failure and relapse, HIV disease progression, T-cell counts and anthropometry was collected routinely, with a median follow-up of 52 and 30 months for HIV-uninfected and HIV-infected patients, respectively. Cox and binomial regression, and generalised estimating equations were used to assess the association of vitamin D status with these outcomes. Mean 25-hydroxyvitamin D concentrations at enrolment were 69.8 (±21.5) nmol/L (27.9 (±8.6) ng/mL). Vitamin D insufficiency (<75 nmol/L) was associated with a 66% higher risk of relapse (95% CI 4% to 164%; 133% higher risk in HIV-uninfected patients). Each unit higher 25-hydroxyvitamin D levels at baseline were associated with a decrease of 3 (p=0.004) CD8 and 3 (p=0.01) CD3 T-cells/µL during follow-up in patients with HIV infection. Vitamin D insufficiency was also associated with a greater decrease of body mass index (BMI; -0.21 kg/m(2); 95% CI -0.39 to -0.02), during the first 8 months of follow-up. No association was observed for vitamin D status with mortality or HIV disease progression. Adequate vitamin D status is associated with a lower risk of relapse and with improved nutritional indicators such as BMI in patients with TB, with or without HIV infection. Further research is needed to determine the optimal dose of vitamin D and effectiveness of daily vitamin D supplementation among patients with TB