Obesity and Malnutrition

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Thermal surveillance of Cascade Range volcanoes using ERTS-1 multispectral scanner, aircraft imaging systems, and ground-based data communication platforms

A combination of infrared images depicting areas of thermal emission and ground calibration points have proved to be particularly useful in plotting time-dependent changes in surface temperatures and radiance and in delimiting areas of predominantly convective heat flow to the earth's surface in the Cascade Range and on Surtsey Volcano, Iceland. In an integrated experiment group using ERTS-1 multispectral scanner (MSS) and aircraft infrared imaging systems in conjunction with multiple thermistor arrays, volcano surface temperatures are relayed daily to Washington via data communication platform (DCP) transmitters and ERTS-1. ERTS-1 MSS imagery has revealed curvilinear structures at Lassen, the full extent of which have not been previously mapped. Interestingly, the major surface thermal manifestations at Lassen are aligned along these structures, particularly in the Warner Valley

There are Flowers in the Graves of our Darlings

https://digitalcommons.library.umaine.edu/mmb-me/1693/thumbnail.jp

Roosting ecology of endangered plant‐roosting bats on Okinawa Island: Implications for bat‐friendly forestry practices

Roosting information is crucial to guiding bat conservation and bat-friendly forestry practices. The Ryukyu tube-nosed bat Murina ryukyuana (Endangered) and Yanbaru whiskered bat Myotis yanbarensis (Critically Endangered) are forest-dwelling bats endemic to the central Ryukyu Archipelago, Japan. Despite their threatened status, little is known about the roosting ecology of these species and the characteristics of natural maternity roosts are unknown. To inform sustainable forestry practices and conservation management, we radio-tracked day roosts of both species in the subtropical forests of Okinawa's Kunigami Village District. We compared roost and roost site characteristics statistically between M. ryukyuana nonmaternity roosts (males or nonreproductive females), maternity roosts, and all M. yanbarensis roosts. Generalized linear models were used to investigate roost site selection by M. ryukyuana irrespective of sex and age class. Lastly, we compiled data on phenology from this and prior studies. Nonreproductive M. ryukyuana roosted alone and primarily in understory foliage. Murina ryukyuana maternity roosts were limited to stands >50 years old, and ~60% were in foliage. Myotis yanbarensis roosted almost entirely in cavities along gulch bottoms and only in stands >70 years old (~1/3 of Kunigami's total forest area). Murina ryukyuana maternity roosts were higher (4.3 ± 0.6 m) than conspecific nonmaternity roosts (2.3 ± 0.5 m; p <.001) and M. yanbarensis roosts (2.7 ± 0.5 m; not significant). Model results were inconclusive. Both species appear to be obligate plant roosters throughout their life cycle, but the less flexible roosting preferences of M. yanbarensis may explain its striking rarity. To conserve these threatened bats, we recommend the following forestry practices: (a) reduce clearing of understory vegetation, (b) refrain from removing trees along streams, (c) promote greater tree cavity densities by protecting old-growth forests and retaining snags, and (d) refrain from removing trees or understory between April and July, while bats are pupping.コウモリのねぐらに関する生態学的な情報はコウモリの保全とそれを考慮する森林の施業のために重要である。リュウキュウテングコウモリMurina ryukyuana（絶滅危惧）とヤンバルホオヒゲコウモリMyotis yanbarensis（絶滅寸前）は森林性コウモリで、日本の琉球列島中部における固有種である。絶滅の恐れがある種にもかかわらず、これらの種のねぐらに関する生態については情報が不足しており、自然条件下における母子集団のねぐらの特徴は明らかになっていない。持続可能な森林施業と保全に関わる情報を提供するために、沖縄島国頭村における亜熱帯林で両種の昼間のねぐらの場所や特徴を、ラジオテレメトリー法によって個体を追跡することによって調査した。リュウキュウテングコウモリの非母子集団ねぐら（雄または非繁殖雌）、母子集団ねぐら、及び全てのヤンバルホオヒゲコウモリのねぐらの間で、ねぐらとねぐらの場所の特徴を統計的に比較した。一般化線形モデルを用いて、性別や年齢階級を考慮しない条件でリュウキュウテングコウモリによるねぐら場所の選好性を調査した。最後に、本研究と先行研究から、ねぐらに関わるフェノロジーに関するデータを収集・整理した。非生殖のリュウキュウテングコウモリは単独で、主に下層植生の葉をねぐらとして利用した。リュウキュウテングコウモリの母子集団のねぐらとしての利用は林齢50年以上の林分に限定され、約60％が葉であった。ヤンバルホオヒゲコウモリはほぼ完全に谷底の樹洞をねぐらとして利用し、ねぐらの形成は林齢70年以上の林分に限られていた（国頭村における森林面積の約1／3）。リュウキュウテングコウモリの母子集団ねぐらは同種の非母子集団ねぐら（2.3 ± 0.5 m; p < .001）とヤンバルホオヒゲコウモリのねぐら（2.7 ± 0.5 m; not significant）より高い位置にあった（4.3 ± 0.6 m）。モデルによる推定結果は決定的ではなかった。両種はライフサイクルの間ずっと偏性的な植物性コウモリであるようだが、ヤンバルホオヒゲコウモリの選好は柔軟性が低く、このことが本種の際だった希少性を説明する可能性がある。これらの絶滅危惧種であるコウモリを保全するためには、以下の森林施業が提案できる：（a）下層植生の除去を少なくすること、（b）渓流沿いの樹木の伐採を控えること、（c）高林齢の森林を保存し、枯死木も除去せず、樹洞の密度を確保すること、（d）コウモリが子育てしている時期である4月〜7月の間に、樹木と下層植生の除去を控えることである

Fully quantum mechanical dynamic analysis of single-photon transport in a single-mode waveguide coupled to a traveling-wave resonator

We analyze the dynamics of single photon transport in a single-mode waveguide coupled to a micro-optical resonator using a fully quantum mechanical model. We examine the propagation of a single-photon Gaussian packet through the system under various coupling conditions. We review the theory of single photon transport phenomena as applied to the system and we develop a discussion on the numerical technique we used to solve for dynamical behavior of the quantized field. To demonstrate our method and to establish robust single photon results, we study the process of adiabatically lowering or raising the energy of a single photon trapped in an optical resonator under active tuning of the resonator. We show that our fully quantum mechanical approach reproduces the semi-classical result in the appropriate limit and that the adiabatic invariant has the same form in each case. Finally, we explore the trapping of a single photon in a system of dynamically tuned, coupled optical cavities.Comment: 24 pages, 10 figure

Truly unentangled photon pairs without spectral filtering

We demonstrate that an integrated silicon microring resonator is capable of efficiently producing photon pairs that are completely unentangled; such pairs are a key component of heralded single photon sources. A dual-channel interferometric coupling scheme can be used to independently tune the quality factors associated with the pump and signal and idler modes, yielding a biphoton wavefunction with Schmidt number arbitrarily close to unity. This will permit the generation of heralded single photon states with unit purity.Comment: 5 pages, 3 figure

Observation of Nonspreading Wave Packets in an Imaginary Potential

We propose and experimentally demonstrate a method to prepare a nonspreading atomic wave packet. Our technique relies on a spatially modulated absorption constantly chiseling away from an initially broad de Broglie wave. The resulting contraction is balanced by dispersion due to Heisenberg's uncertainty principle. This quantum evolution results in the formation of a nonspreading wave packet of Gaussian form with a spatially quadratic phase. Experimentally, we confirm these predictions by observing the evolution of the momentum distribution. Moreover, by employing interferometric techniques, we measure the predicted quadratic phase across the wave packet. Nonspreading wave packets of this kind also exist in two space dimensions and we can control their amplitude and phase using optical elements.Comment: 4 figure

Carrier velocity in InAlN/AlN/GaN heterostructure field effect transistors on Fe-doped bulk GaN substrates

We report microwave characteristics of field effect transistors employing InAlN/AlN/GaN heterostructures grown on low-defect-density bulk Fe-doped GaN substrates. We achieved unity current gain cutoff frequencies of 14.3 and 23.7 GHz for devices with gate lengths of 1 and 0.65 μm, respectively. Measurements as a function of applied bias allow us to estimate the average carrier velocity in the channel to be ∼1.0×107 cm/sec for a 1 μm device. Additionally, we found nearly no gate lag in the devices, which is considered a precondition for good performance under large signal operation

Effect of hot phonon lifetime on electron velocity in InAlN/AlN/GaN heterostructure field effect transistors on bulk GaN substrates

We report on electron velocities deduced from current gain cutoff frequency measurements on GaN heterostructurefield effect transistors(HFETs) with InAlN barriers on Fe-doped semi-insulating bulk GaN substrates. The intrinsic transit time is a strong function of the applied gate bias, and a minimum intrinsic transit time occurs for gate biases corresponding to two-dimensional electron gas densities near 9.3×1012 cm−2. This value correlates with the independently observed density giving the minimum longitudinal optical phonon lifetime. We expect the velocity, which is inversely proportional to the intrinsic transit time, to be limited by scattering with non equilibrium (hot) phonons at the high fields present in the HFET channel, and thus, we interpret the minimum intrinsic transit time in terms of the hot phonon decay. At the gate bias associated with the minimum transit time, we determined the average electron velocity for a 1.1 μm gate length device to be 1.75±0.1×107 cm/sec