Influence of neutron irradiation on the thermal conductivity of vapor‐deposited diamond

The influence of neutron irradiation on the thermal conductivity κ of diamond films fabricated by hot filament (HF) and microwave plasma assisted (MPA) deposition has been studied. The additional thermal resistivity induced by irradiation is similar to that found in single crystal diamond and is due mainly to the formation of clusters of disordered carbon material. Despite a significant difference in κ prior to irradiation, the thermal conductivity of the HF and MPA films is almost the same after a cumulative dose of 2.7×1017 neutrons cm−2.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69811/2/JAPIAU-76-3-1515-1.pd

Correlating optical absorption and thermal conductivity in diamond

The presence of defects in diamond induces one‐phonon infrared absorption which is not allowed in the perfect crystal due to symmetry. Concomitantly the thermal conductivity is reduced by additional phonon‐defect scattering. For single crystal diamonds irradiated with fast neutrons, we find a correlation between the one‐phonon absorption and the room‐temperature thermal conductivity valid over three orders of magnitude in defect concentration. This relation holds for both unannealed and annealed crystals for which the detailed configuration of defects is different, as well as for a synthetic diamond film containing a similar type of disorder. Infrared absorption can thus be used to determine the thermal conductivity of diamonds containing vacancy‐related defect centers.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70107/2/APPLAB-63-2-165-1.pd

Hepatitis C virus genotypes in liver transplant recipients: Impact on posttransplant recurrence, infections, response to interferon-α therapy and outcome

Background. End-stage liver disease due to hepatitis C virus (HCV) is the most common indication for liver transplantation in U.S. veterans. We investigated the influence of HCV genotypes on the incidence and timing of recurrent HCV hepatitis, survival, infectious morbidity, and response to interferon-α therapy in this unique patient population. Methods. HCV genotype was determined by direct sequencing of the NS5 region of HCV with type-specific primers. Results. Genotype 1a (66%, 32/47) was the predominant genotype. Type 1b was found in 25% (12/47) of patients and type 2b was found in 9% (4/47). His topathologically recurrent HCV hepatitis developed in 53% (25/47) of the patients after transplantation. This group included 45% (14/31) of the patients with type 1a, 67% (8/12) of the patients with type 1b, and 25% (1/4) of the patients with type 2b (P>0.5). The time to recurrence and the severity of HCV recurrence as defined by aminotransferase levels or Knodell scores were not different among the three genotypes. There was a trend toward a higher incidence of major infections in patients with type 1b (75%) versus type 1a (48%) and type 2b (50%) (P=0.11). The response to interferon-α therapy did not differ significantly among the genotypes. Mortality at 5 years was 16% (5/31) in patients with genotype 1a, 42% (5/12) in patients with genotype 1b, and 50% (2/4) in patients with genotype 2b (P=0.06). Conclusions. The incidence, time to recurrence, and response to interferon-α therapy did not differ be tween the various genotypes in our liver transplant recipients. However, there was a trend toward higher infectious morbidity and overall mortality in patients with genotype 1b after transplantation

Articulating social welfare PhD program rubrics toward sustainable assessment

The Myron B. Thompson School of Social Work (SW) PhD program at the University of Hawaiʻi at Mānoa currently has 16 students and 10 graduate faculty members. Developing and implementing sustainable PhD assessment plans are necessary to reflect student learning and curriculum improvements. Articulating the PhD program rubrics into a program-level assessment plan is imperative. The SW PhD program has developed seven Student Learning Outcomes (SLOs), assessable outcomes, and a curriculum map. In Fall of 2015, the PhD program committee revisited the SLOs and made revisions in alignment with the sustainable assessment plan for the program as a foundational step for creating program rubrics. The committee developed program rubrics for benchmarks—(a) specialization, (b) comprehensive examination (i.e., dissertation proposal), and (c) final exam (i.e., dissertation defense)—that are tied to the SLOs. The committee began collecting data using developed rubrics in Spring 2016 as a pilot to gain additional clarity on the rubrics in order to make them efficient and manageable as key parts of PhD program curriculum. During the process of developing the rubrics, the PhD committee collaborated to facilitate the assessment planning process. During this assessment process, the committee has utilized existing materials and sources, such as student products (e.g., dissertation proposal), evaluation criteria (e.g., dissertation evaluation), yearly advising sessions, and student reviews materials. This poster presents the strategies utilized in the pilot project as well as lessons learned through the project

Distinguishing low frequency mutations from RT-PCR and sequence errors in viral deep sequencing data

There is a high prevalence of coronary artery disease (CAD) in patients with left bundle branch block (LBBB); however there are many other causes for this electrocardiographic abnormality. Non-invasive assessment of these patients remains difficult, and all commonly used modalities exhibit several drawbacks. This often leads to these patients undergoing invasive coronary angiography which may not have been necessary. In this review, we examine the uses and limitations of commonly performed non-invasive tests for diagnosis of CAD in patients with LBBB

Large-scale wind-tunnel tests of inverting flaps on a STOL utility aircraft model

A unique inverting flap system was investigated on a large scale deflected slipstream model in the Ames 40 by 80 foot wind tunnel. The subject tests utilized 33% chord double-slotted flaps on a low aspect ratio wing that was fully immersed in the propeller slipstream. Evaluation of the flap effectiveness is aided by comparisons with the results of tests of other flap systems on the same twin propeller, twin tail boom STOL utility aircraft mode. No extreme or abrupt force or moment increments were encountered when the flaps were deflected through a wide range, corresponding to the complete retraction/extension spectrum. The lift and descent capability of the inverting flaps compared very favorably with that of the other flap systems that have been tested on this model, including some with much greater mechanical complexity. As expected, the flaps caused large nose down, pitching moment increments at the high lift settings; however, the trimmed characteristics are still competitive with those obtained from the more complicated flap systems. It is believed that these flaps may have promising potential application to the design of relatively simple STOL utility aircraft with improved performance capabilities. In addition, they may merit consideration as retrofits to existing aircraft with less effective flap systems

Timing Synchronization and Channel Estimation in Free-Space Optical OOK Communication Systems

Fast and reliable synchronization in free-space optical (FSO) communications is a crucial task that has received little attention so far. Since in these applications the data rate is much higher than in traditional radio-frequency (RF) systems, novel technological constraints may arise in the design of the synchronization algorithms, as for example the need to operate at symbol rate instead with an oversampled data stream. In this work, we consider an FSO link and investigate the problem of channel estimation, symbol timing recovery and frame detection using a known synch pattern. The modulation format is on-off keying (OOK) and the received signal is plagued by a mixture of thermal and shot noise. By applying the least-squares criterion, we derive a novel synchronization scheme that can jointly retrieve all the unknown parameters using symbol-spaced samples. Although designed without taking the noise statistics into account, the estimator performance is assessed in a realistic scenario where shot noise is present. Comparisons are made with the relevant Cramér-Rao bound for the joint estimation of the synchronization parameters and signal-dependent noise variances. Numerical simulations and complexity analysis indicate that the resulting scheme performs satisfactorily with an affordable processing load. Hence, it represents a promising solution for fast synchronization in high-speed FSO communications