Infrared Fiber Systems (United States)

Why do US college-educated couples with children marry at higher rates than those without a college degree? We argue that investing in children is more valuable for college-educated couples, who are more likely to send their children to college. Marriage, which entails lower separation risk and more equal asset division if separation does occur, provides insurance to the lower-earning spouse, which facilitates child investment. Using an OLG model of marriage, cohabitation, wealth accumulation, and educational investments where college completion is risky, we find that insurance through marriage is particularly important when investing in children is costly and college costs are high.

Controversy exists regarding whether violent shaking is harmful to infants in the absence of impact. In this study, our objective was to characterize the biomechanical response of the infant head during shaking through use of an instrumented anthropomorphic test device (commonly referred to as a "crash test dummy" or surrogate) representing a human infant and having improved biofidelity. A series of tests were conducted to simulate violent shaking of an infant surrogate. The Aprica 2.5 infant surrogate represented a 5th percentile Japanese newborn. A 50th percentile Japanese adult male was recruited to shake the infant surrogate in the sagittal plane. Triaxial linear accelerometers positioned at the center of mass and apex of the head recorded accelerations during shaking. Five shaking test series, each 3-4 sec in duration, were conducted. Outcome measures derived from accelerometer recordings were examined for trends. Head/neck kinematics were characterized during shaking events; mean peak neck flexion was 1.98 radians (113 degrees) and mean peak neck extension was 2.16 radians (123 degrees). The maximum angular acceleration across all test series was 13,260 radians/sec2 (during chin-to-chest contact). Peak angular velocity was 105.7 radians/sec (during chin-to-chest contact). Acceleration pulse durations ranged from 72.1 to 168.2 ms. Using an infant surrogate with improved biofidelity, we found higher angular acceleration and higher angular velocity than previously reported during infant surrogate shaking experiments. Findings highlight the importance of surrogate biofidelity when investigating shaking.

Overview paper for the Special Issue of LLCS

毛髪の水分量を加熱重量減量法で実測し，前処理後の近赤外（NIR）スペクトルで重回帰分析による水分予測を行った結果，加熱重量減量法での値とNIR予測値の相関はr2＝0.957であり，スペクトルから毛髪の水分予測が可能であることが分かった．また，クラウジウス-クラペイロンの式の類推から∂(lnw)/∂(1/T)＝ΔH/Rという式を導き，毛髪内の水分の保湿力（毛髪内の水の蒸発のしにくさ）の違いは蒸発エンタルピーΔH/kJ/molの違いであると考えた．10名の対象により20～100℃ までの温度での毛髪の水分量を測定し，ΔHを（ln[w/mol/kg]）vs. （1/T）プロットの傾きから得た．その結果について，純水のΔH（43.991 kJ/mol）との比較から，個人の毛髪の保湿力の大小を議論できることが分かった．

We begin with a brief review of prior work relating to optical windows for use with high power laser beams. A typical window must provide pressure separation between system segments, ultra-low loss, and small wavefront distortion of the many outgoing laser beams and signal returns despite heating by the high energy laser beam. Historically, two approaches have been examined to improve such windows.

Pulses from a commercial Er:YAG laser (Quantronics, Smithtown) have been transmitted through prototype commercial zirconium fluoride optical fibers (Infrared Fiber Systems, Silver Spring) to ablate atheromatous arteries in a wet field in order to evaluate the feasibility of such a system for laser angioplasty.