Optimizing an array of antennas for cellular coverage from a high altitude platform

In a wireless communications network served by a high altitude platform (HAP) the cochannel interference is a function of the antenna beamwidth, angular separation and. sidelobe level. At the millimeter wave frequencies proposed for HAPs, an array of aperture type antennas on the platform is a practicable solution for serving the cells. We present a method for predicting cochannel interference based on curve-fit approximations for radiation patterns of elliptic beams which illuminate cell edges with optimum power, and a means of estimating optimum beamwidths for each cell of a regular hexagonal layout. The method is then applied to a 121 cell architecture. Where sidelobes are modeled As a flat floor at 40-dB below peak directivity, a cell cluster size of four yields carrier-to-interference ratios (CIRs), which vary from 15 dB at cell edges to 27 dB at cell centers. On adopting a cluster size of seven, these figures increase, respectively, to 19 and 30 dB. On reducing the sidelobe level, the. improvement in CIR can be quantified. The method also readily allows for regions of overlapping channel coverage to be shown

An Extended Culture System that Supports Human Primordial Germ Cell-like Cell Survival and Initiation of DNA Methylation Erasure.

The development of an in vitro system in which human primordial germ cell-like cells (hPGCLCs) are generated from human pluripotent stem cells (hPSCs) has been invaluable to further our understanding of human primordial germ cell (hPGC) specification. However, the means to evaluate the next fundamental steps in germ cell development have not been well established. In this study we describe a two dimensional extended culture system that promotes proliferation of specified hPGCLCs, without reversion to a pluripotent state. We demonstrate that hPGCLCs in extended culture undergo partial epigenetic reprogramming, mirroring events described in hPGCs in vivo, including a genome-wide reduction in DNA methylation and maintenance of depleted H3K9me2. This extended culture system provides a new approach for expanding the number of hPGCLCs for downstream technologies, including transplantation, molecular screening, or possibly the differentiation of hPGCLCs into gametes by in vitro gametogenesis

Nurses\u27 Alumnae Association Bulletin, December 1968

President\u27s Message Officers and Committee Chairman Financial Report Report to Alumnae Association Annual Report to Alumnae Association School of Practical Nursing Report Student Activities Nursing Service Staff Association Letter from Vietnam Resume of Alumnae Meetings Ways and Means Report Social Committee Building Fund Report Bulletin Committee Report Class News Notice

Pola Komunikasi Pemimpin Organisasi Dalam Meningkatkan Motivasi Kerja Anggota Di LPM (Lembaga Pers Mahasiswa) Inovasi Unsrat

Penelitian ini dengan judul Pola Komunikasi Pemimpin Organisasi Dalam Meningkatkan Motivasi Kerja Anggota Di LPM (lembaga pers mahasiswa) Inovasi Unsrat, dengan focus penelitian adalah : Bagaimana komunikasi pemimpin organisasi dalam aspek orientasi kerja. Kemudian tentang bagaimana komunikasi pemimpin organisasi dalam aspek orientasi hubungan. Dan juga bagaimana komunikasi pemimpin organisasi dalam aspek keefektifan. Penelitian ini menggunakan pendekatan metode kualitatif sebagai prosedur penelitian yang menghasilkan data deskriptif berupa kata-kata atau lisan dari orang-orang dan perilaku yang dapat diamati. Teori yang digunakan dalam penelitian ini adalah teori Reddin, mendapatkan hasil penelitian sebagai berikut : (1). Aspek Orientasi-Kerja. Pemimpin Organisasi di LPM Inovasi Unsrat memberikan pemahaman kepada anggota agar dapat mengerti tugas yang diberikan, serta motivasi yang dapat membuat anggota menjadi giat bekerja. Anggota juga berusaha untuk memahami dan termotivasi agar dapat bekerja dengan baik. Komunikasi yang dilakukan dalam meningkatkan motivasi kerja anggota adalah dengan menggunakan komunikasi kelompok medium group yaitu komunikasi dalam kelompok sedang lebih mudah karena dapat diorganisir dengan baik dan terarah, misalnya komunikasi antara satu bidang dengan bidang yang lain dalam organisasi. (2) Aspek Orientasi-Hubungan. Pemimpin organisasi selalu menciptakan hubungan yang baik dengan anggota, begitupun sebaliknya dengan anggota. Komunikasi antara pemimpin dan anggota dalam menciptakan hubungan yang baik dalam organisasi yaitu dengan menggunakan komunikasi antar personal yaitu komunikasi yang terjadi antar komunikator dengan komunikan secara langsung dengan cara berhadapan muka atau tidak. Komunikasi seperti ini lebih efektif karena kedua belah pihak saling melancarkan komunikasinya dan dengan feedback keduanya melaksanakan fungsi masing-masing. Untuk itu pemimpin harus mampu menyediakan waktu untuk dapat berbincang dengan para anggota, sekaligus mengatasi kendala-kendala yang menjadi pemicu keterlambatan dalam penyelesaian tugas. Hal ini juga akan memunculkan berbagai tanggapan ataupun masukkan dari para anggota, yang harus diterima oleh pemimpin organisasi. (3) Aspek Keefektifan. Setiap tugas yang diberikan tidak selalu dapat diselesaikan sesuai target dan tepat waktu, namun pemimpin selalu berusaha untuk mengupayakan agar pencapaian produksi seperti pembuatan majalah tahunan dapat terselesaikan dengan baik dan tepat waktu sesuai deadline. Tidak bisa efektif juga karena kendala yang dihadapi oleh organisasi yang menjadi faktor utama yaitu dana. Pencairan dana yang diproses melalui pengelola Gedung PKM Unsrat, bisa diproses cukup lama, karena pengecekan dilakukan dengan prosedur-prosedur yang telah ditetapkan

Detection limits of organic compounds achievable with intense, short-pulse lasers

Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization. This resonant multiphoton ionization scheme has already been exploited as an ionization source in time-of-flight mass spectrometers used for environmental trace analysis. In the present work we quantify the ultimate potential of this technique by measuring absolute ion yields produced from the interaction of 267 nm femtosecond laser pulses with the organic molecules indole and toluene, and gases Xe, N2 and O2. Using multiphoton ionization cross sections extracted from these results, we show that the laser pulse parameters required for real-time detection of aromatic molecules at concentrations of one part per trillion in air and a limit of detection of a few attomoles are achievable with presently available commercial laser systems. The potential applications for the analysis of human breath, blood and tissue samples are discussed

LArPix: Demonstration of low-power 3D pixelated charge readout for liquid argon time projection chambers

We report the demonstration of a low-power pixelated readout system designed for three-dimensional ionization charge detection and digital readout of liquid argon time projection chambers (LArTPCs). Unambiguous 3D charge readout was achieved using a custom-designed system-on-a-chip ASIC (LArPix) to uniquely instrument each pad in a pixelated array of charge-collection pads. The LArPix ASIC, manufactured in 180 nm bulk CMOS, provides 32 channels of charge-sensitive amplification with self-triggered digitization and multiplexed readout at temperatures from 80 K to 300 K. Using an 832-channel LArPix-based readout system with 3 mm spacing between pads, we demonstrated low-noise ($<$500 e$^-$ RMS equivalent noise charge) and very low-power ($<$100 $\mu$W/channel) ionization signal detection and readout. The readout was used to successfully measure the three-dimensional ionization distributions of cosmic rays passing through a LArTPC, free from the ambiguities of existing projective techniques. The system design relies on standard printed circuit board manufacturing techniques, enabling scalable and low-cost production of large-area readout systems using common commercial facilities. This demonstration overcomes a critical technical obstacle for operation of LArTPCs in high-occupancy environments, such as the near detector site of the Deep Underground Neutrino Experiment (DUNE).Comment: 19 pages, 10 figures, 1 ancillary animation. V3 includes minor revisions based on referee comment

Changes in growth of tropical forests: evaluating potential biases

Over the past century almost every ecosystem on Earth has come under the influence of changes in atmospheric composition and climate caused by human activity. Tropical forests are among the most productive and extensive ecosystems, and it has been hypothesized that both the dynamics and biomass of apparently undisturbed, old-growth tropical forests have been changing in response to atmospheric changes. Long-term forest sample plots are a critical tool in detecting and monitoring such changes, and our recent analysis of pan-tropical-forest plot data has suggested that the biomass of tropical forests has been increasing, providing a modest negative feedback on the rate of accumulation of atmospheric CO2. However, it has been argued that some of these old forest plot data sets have significant problems in interpretation because of the use of nonstandardized methodologies. In this paper we examine the extent to which potential field methodological errors may bias estimates of total biomass change by detailed examination of tree-by-tree records from up to 120 Neotropical plots to test predictions from theory. Potential positive biases on measurements of biomass change include a bias in site selection, tree deformities introduced by the measurement process, poor methodologies to deal with tree deformities or buttresses, and nonrecording of negative growth increments. We show that, while it is important to improve and standardize methodologies in current and future forest-plot work, any systematic errors introduced by currently identified biases in past studies are small and calculable. We conclude that most tropical-forest plot data are of useful quality, and that the evidence does still weigh conclusively in favor of a recent increase of biomass in old-growth tropical forests

Implications of Electronics Constraints for Solid-State Quantum Error Correction and Quantum Circuit Failure Probability

In this paper we present the impact of classical electronics constraints on a solid-state quantum dot logical qubit architecture. Constraints due to routing density, bandwidth allocation, signal timing, and thermally aware placement of classical supporting electronics significantly affect the quantum error correction circuit's error rate. We analyze one level of a quantum error correction circuit using nine data qubits in a Bacon-Shor code configured as a quantum memory. A hypothetical silicon double quantum dot quantum bit (qubit) is used as the fundamental element. A pessimistic estimate of the error probability of the quantum circuit is calculated using the total number of gates and idle time using a provably optimal schedule for the circuit operations obtained with an integer program methodology. The micro-architecture analysis provides insight about the different ways the electronics impact the circuit performance (e.g., extra idle time in the schedule), which can significantly limit the ultimate performance of any quantum circuit and therefore is a critical foundation for any future larger scale architecture analysis.Comment: 10 pages, 7 figures, 3 table

Mechanisms explaining transitions between tonic and phasic firing in neuronal populations as predicted by a low dimensional firing rate model

Several firing patterns experimentally observed in neural populations have been successfully correlated to animal behavior. Population bursting, hereby regarded as a period of high firing rate followed by a period of quiescence, is typically observed in groups of neurons during behavior. Biophysical membrane-potential models of single cell bursting involve at least three equations. Extending such models to study the collective behavior of neural populations involves thousands of equations and can be very expensive computationally. For this reason, low dimensional population models that capture biophysical aspects of networks are needed. \noindent The present paper uses a firing-rate model to study mechanisms that trigger and stop transitions between tonic and phasic population firing. These mechanisms are captured through a two-dimensional system, which can potentially be extended to include interactions between different areas of the nervous system with a small number of equations. The typical behavior of midbrain dopaminergic neurons in the rodent is used as an example to illustrate and interpret our results. \noindent The model presented here can be used as a building block to study interactions between networks of neurons. This theoretical approach may help contextualize and understand the factors involved in regulating burst firing in populations and how it may modulate distinct aspects of behavior.Comment: 25 pages (including references and appendices); 12 figures uploaded as separate file

An international network to monitor the structure, composition and dynamics of Amazonian forests (RAINFOR)

The Amazon basin is likely to be increasingly affected by environmental changes: higher temperatures, changes in precipitation, CO2 fertilization and habitat fragmentation. To examine the important ecological and biogeochemical consequences of these changes, we are developing an international network, RAINFOR, which aims to monitor forest biomass and dynamics across Amazonia in a co-ordinated fashion in order to understand their relationship to soil and climate. The network will focus on sample plots established by independent researchers, some providing data extending back several decades. We will also conduct rapid transect studies of poorly monitored regions. Field expeditions analysed local soil and plant properties in the first phase (2001–2002). Initial results suggest that the network has the potential to reveal much information on the continental-scale relations between forest and environment. The network will also serve as a forum for discussion between researchers, with the aim of standardising sampling techniques and methodologies that will enable Amazonian forests to be monitored in a coherent manner in the coming decades