Multi-axis heterodyne interferometry at MHz frequencies: a short-arm measurement demonstration for LISA with off-the-shelf hardware.

We report the design, construction, and operation of a multi-axis heterodyne interferometry (MAHI) system operating at MHz heterodyne frequencies, which provides a testbed for technologies to be used in the Laser Interferometer Space Antenna (LISA) space-based gravitational wave mission. The system was calibrated for measurement of the piston, pitch, and yaw of a three-axis piezo-actuated mirror, giving measured calibration values that closely match those predicted by a simulation based on Gaussian beam tracing. The piston sensitivity of the MAHI system in the LISA band was measured to be below 10 pm Hz-1/2 for frequencies above 4 mHz and below 1 pm Hz-1/2 for frequencies above 35 mHz. The sensitivity is limited above 2 Hz by the mechanical vibrations of the apparatus and below 1 mHz by dimensional changes caused by temperature fluctuations. Evidence points towards scattered light as the limiting noise source at intermediate frequencies. The angular sensitivity of the MAHI system was measured to be close to or below 10 nrad Hz-1/2 for frequencies above 4 mHz and below 1 nrad Hz-1/2 for frequencies above 100 mHz. Noise budgets for both length and angle were determined, indicating the areas in which improvements must be made in order to reach increased sensitivity. The current operating sensitivity already provides a useful testbed for LISA technologies and a potential blueprint for future ground segment equipment.

Effects of transients in LIGO suspensions on searches for gravitational waves.

This paper presents an analysis of the transient behavior of the Advanced LIGO (Laser Interferometer Gravitational-wave Observatory) suspensions used to seismically isolate the optics. We have characterized the transients in the longitudinal motion of the quadruple suspensions during Advanced LIGO's first observing run. Propagation of transients between stages is consistent with modeled transfer functions, such that transient motion originating at the top of the suspension chain is significantly reduced in amplitude at the test mass. We find that there are transients seen by the longitudinal motion monitors of quadruple suspensions, but they are not significantly correlated with transient motion above the noise floor in the gravitational wave strain data, and therefore do not present a dominant source of background noise in the searches for transient gravitational wave signals. Using the suspension transfer functions, we compared the transients in a week of gravitational wave strain data with transients from a quadruple suspension. Of the strain transients between 10 and 60 Hz, 84% are loud enough that they would have appeared above the sensor noise in the top stage quadruple suspension monitors if they had originated at that stage at the same frequencies. We find no significant temporal correlation with the suspension transients in that stage, so we can rule out suspension motion originating at the top stage as the cause of those transients. However, only 3.2% of the gravitational wave strain transients are loud enough that they would have been seen by the second stage suspension sensors, and none of them are above the sensor noise levels of the penultimate stage. Therefore, we cannot eliminate the possibility of transient noise in the detectors originating in the intermediate stages of the suspension below the sensing noise.

Comparison of outcomes after TURP versus photoselective vaporization of the prostate with respect to trainee involvement utilizing ACS NSQIP.

BACKGROUND: Large multicenter studies comparing outcomes between TURP and photoselective vaporization of the prostate (PVP) are sparse, with no studies having compared the influence of trainee involvement on these outcomes. Our objectives were to assess 30-day outcomes after TURP and PVP with respect to trainee involvement using an independent national surgical database. METHODS: Using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) data (2005-2011), 7893 men were identified who underwent TURP or PVP. Regression models were constructed to assess associations between surgical approach, risk-adjusted morbidity and individual complications. Relationships between operative approach, operative duration and duration of stay were also examined and subdivided based upon trainee level. RESULTS: Of 7893 patients, 4950 (62.7%) underwent TURP and 2943 (37.3%) underwent PVP. TURP patients were older, more likely to have diabetes, cancer, history of steroid use and preoperative transfusion compared with PVP patients, who were more likely to have coronary artery disease or bleeding disorders. Risk-adjusted overall morbidity was similar; however, PVP was associated with less pneumonia (0.2% vs 0.5%, P<0.015), bleeding requiring transfusion (0.5% vs 1.8%, P<0.001) and return to the operating room (1.5% vs 2.2%, P<0.022). PVP patients also had shorter length of stay (0.8 vs 2.1 days, P<0.001). There were no significant differences in outcomes when a trainee was involved. Operative duration was similar for TURP and PVP when performed by an attending alone (52 vs 52 min, P<0.001), but was longer with trainee involvement, regardless of post-graduate year (PGY) level (P<0.001). Comparison of operative duration among trainee subgroups demonstrated longer operative times for the PGY 6-9 subgroup performing PVP when compared with other subgroups (P<0.003). CONCLUSIONS: Within ACS NSQIP hospitals, TURP and PVP demonstrated similar risk-adjusted overall morbidity. Despite longer operative times for TURP and PVP with trainee involvement, there were no significant differences in outcomes.

Psychiatric disorders in adolescents exposed to domestic violence and physical abuse.

The relationship between abuse and psychiatric diagnoses was investigated in two groups of physically abused adolescents, 57 living in homes with interparental violence and 32 in homes without such violence, and in 96 nonabused adolescents living in nonviolent homes. Adolescents in the first group were found to be at greater risk for depression, separation anxiety disorder, post-traumatic stress disorder, and oppositional defiant disorder than were those in the second group. Adolescents in the first group also appeared more vulnerable to anxiety and depression.

Laparoscopic tension-free repair of large paraesophageal hernias.

The paraesophageal hernia is an unusual disorder of the esophageal hiatus that may be associated with life-threatening mechanical problems. Elective repair is recommended at the time the condition is diagnosed, and open surgery can be accomplished with a low incidence of complications. The option of performing these repairs through a laparoscopic approach may further reduce morbidity and recovery time associated with surgical intervention. The purpose of this report was to review available options for laparoscopic repair and to present our experience with a tension-free technique for large paraesophageal hernias. Three patients with large diaphragmatic defects had laparoscopic repairs using an expanded polytetrafluorethylene (PTFE) patch secured with intracorporeal suturing techniques. One of these patients also underwent laparoscopic Toupet fundoplication in conjunction with repair of the hernia. In the other two patients, the fundus was secured to the right diaphragmatic crus to reduce the potential for recurrence and minimize postoperative reflux symptoms. All patients underwent successful repair without perioperative complications and had excellent long-term results. Laparoscopic repair of paraesophageal hernias can be accomplished by a number of different reported techniques. The use of a tension-free repair with PTFE may be particularly suitable for large diaphragmatic defects. An antireflux operation may be added selectively depending on clinical circumstances.

In utero diagnosis of benign fetal macrocephaly.

Benign familial macrocephaly is an autosomal dominant disorder associated with a large absolute circumference of the head. In this disorder serial growth demonstrates a proportional rather than an excessive rate of growth. To date, we are not aware of any published case reports that confirm the diagnosis prenatally. We report a case of benign familial macrocephaly diagnosed in utero by ultrasonographic evaluation. This case report points out the necessity of combining appropriate family history and physical examination in cases of prenatally detected anomalies.

Fine structure of comparable synapses in a mature and larval lobster muscle.

Neuromuscular synapses from the single excitor axon to the proximal accessory flexor muscle (PAFM) was studied by serial section electron microscopy in a 1st stage larval (less than 0.1 g) and a large adult (6.8 kg) lobster. The adult innervation of a lateral and a medial fiber, physiologically identified as low- and high-output respectively, was similar in the number and mean size of synapses but had significantly larger pre-synaptic dense bars for the high-output synapses. This correlation between quantal transmitter output and pre-synaptic dense bars and the appearance of exocytotic profiles along the dense bars strongly implicates the bars as active sites of transmitter release. Moreover the mature innervation is differentiated on the basis that the percentage of dense bar area to synaptic area is 9% for the low-output type compared to 22% for its high-output counterpart. In the larval PAFM the excitatory axon has not proliferated many branches and the innervation is therefore localized to groups of fibers in the lateral, medial and central regions of the muscle rather than to individual fibers. The lateral and medial sites of innervation representing putative low- and high-output types respectively (because of their location) do not differ in the size and number of pre-synaptic dense bars thereby suggesting a similarity in quantal synaptic transmission. However, the percentage of dense bar area to synaptic area is 40% for the lateral site compared to 67% for the medial site. Since this is a trend mimicking the mature innervation it shows an early stage in the differentiation of low- and high-output synapses. Furthermore the main axon provides half of the total innervation in the larval PAFM but none in the adult thereby demonstrating a restructuring of multiterminal innervation.