Sensorimotor integration is affected by acute whole-body vibration: a coherence study.

Introduction: Several whole-body vibration (WBV) effects on performance have been related to potential changes in the neural drive, motor unit firing rate, and sensorimotor integration. In the present paper, motor unit coherence analysis was performed to detect the source of neural modulation based on the frequency domain. Methods: Thirteen men [25 ± 2.1 years; Body Mass Index (BMI) = 23.9 ± 1.3 kg m2; maximal voluntary force (MVF): 324.36 ± 41.26 N] performed sustained contractions of the Tibialis Anterior (TA) at 10%MVF before and after acute WBV. The vibrating stimulus was applied barefoot through a platform to target the TA. High-Density surface Electromyography (HDsEMG) was used to record the myoelectrical activity of TA to evaluate coherence from motor unit cumulative spike-trains (CSTs). Results: Mean coherence showed a significant decrease in the alpha and low-beta bandwidths (alpha: from 0.143 ± 0.129 to 0.132 ± 0.129, p = 0.035; low-beta: from 0.117 ± 0.039 to 0.086 ± 0.03, p = 0.0001), whereas no significant changes were found in the other ones (p > 0.05). The discharge rate (DR) and the Force Covariance (CovF%) were not significantly affected by acute WBV exposure (p > 0.05). Discussion: According to the significant effects found in alpha and low-beta bandwidths, which reflect sensorimotor integration parameters, accompanied by no differences in the DR and CovF%, the present results underlined that possible neural mechanisms at the base of the previously reported performance enhancements following acute WBV are likely based on sensorimotor integration rather than direct neural drive modulation.

The acute effects of whole-body vibration on motor unit recruitment and discharge properties.

Introduction: several studies have reported improved neuromuscular parameters in response to whole-body vibration (WBV). This is likely achieved by modulation of the central nervous system (CNS). Reduced recruitment threshold (RT), which is the % of Maximal Voluntary Force (%MVF) at which a given Motor Unit (MU) is recruited, may be responsible for the force/power improvements observed in several studies. Methods: 14 men (25 ± 2.3 years; BMI = 23.3 ± 1.5 kg m2 MVF: 319.82 ± 45.74 N) performed trapezoidal isometric contractions of the tibialis anterior (TA) at 35-50-70 %MVF before and after three conditions: WBV, STAND (standing posture), and CNT (no intervention). The vibration was applied through a platform for targeting the TA. High-density surface electromyography (HDsEMG) recordings and analysis were used to detect changes in the RT and Discharge Rate (DR) of the MUs. Results: Mean motor unit recruitment threshold (MURT) reached 32.04 ± 3.28 %MVF before and 31.2 ± 3.72 %MVF after WBV, with no significant differences between conditions (p > 0.05). Additionally, no significant changes were found in the mean motor unit discharge rate (before WBV: 21.11 ± 2.94 pps; after WBV: 21.19 ± 2.17 pps). Discussion: The present study showed no significant changes in motor unit properties at the base of neuromuscular changes documented in previous studies. Further investigations are needed to understand motor unit responses to different vibration protocols and the chronic effect of vibration exposure on motor control strategies.

Fine tuning of conversion/dispersion based optical delays with a 1 pm tunable laser using cascaded acousto-optic mixing.

We demonstrate a technique for fine tuning of optical delays using cascaded acousto-optic modulators to improve the delay resolution by 5 orders of magnitude compared to a 1 pm tunable laser. A 256 ns delay with <0.5 ps resolution is shown for 40 Gbits/s return-to-zero on-off keying with no added penalty.

Higher-order dispersion compensation to enable a 3.6 micros wavelength-maintaining delay of a 100 Gb/s DQPSK signal.

We demonstrate a method for dispersion slope compensation of a conversion/dispersion-based optical delay to enable 100 Gb/s operation based on a spatial light modulator and fiber Bragg gratings. A continuous delay of up to 3.6 micros for 100, 80, and 20 Gb/s differential quadrature phase-shift-keyed (DQSPK) and 50, 40, and 10 Gb/s differential phase-shift-keyed (DPSK) waveforms is shown. A time-delay bit-rate product of approximately 360,000 for 100 Gb/s DQPSK with wavelength-maintaining operation is achieved.

Continuously tunable 1.16 micros optical delay of 100 Gbit/s DQPSK and 50 Gbit/s DPSK signals using wavelength conversion and chromatic dispersion.

We demonstrate a variable optical delay element that uses tunable wavelength conversion and phase conjugation in highly nonlinear fiber and uses chromatic dispersion in dispersion-compensating fiber. A continuous delay of up to 1.16mus, equaling a >110,000 time-delay bit-rate product for 100 Gbit/s non-return-to-zero differential quadrature phase-shift-keying (NRZ-DQSPK) and >55,000 for 50 Gbit/s NRZ differential phase-shift-keying (NRZ-DPSK) modulation formats, is demonstrated. Bit error rates <10(-9) are demonstrated for each waveform at various delay settings.

Variable rate, multi-format receiver design for 10 to 40 Gb/s DPSK and OOK formats.

We demonstrate a continuously-variable bit-rate receiver from 10 to 40 Gbit/s for DPSK demodulation. Unlike previous DPSK demodulators, this receiver is also capable of passing intensity modulated waveforms without distortion. Degradations imposed by receiver imperfections are presented and compared with a traditional DPSK delay-line interferometer.

Prevention and management of postoperative nausea and vomiting.

PURPOSE: To identify factors associated with the occurrence of postoperative nausea and vomiting and to identify the effectiveness of independent and interdependent nursing interventions for the prevention and management of postoperative nausea and vomiting. DESIGN: Descriptive. SAMPLE: A convenience sample of 300 patients, 18 years or older, who had surgery with general anesthesia (excluding persons having ear or gastrointestinal surgery), at either campus of a large metropolitan medical center. METHOD: A combination of closed chart review and data collection by staff nurses assigned to the patients in the postoperative period using a standardized data collection tool. FINDINGS: Data was analyzed using a combination of descriptive and parametric statistics. There was a 39% incidence of nausea and vomiting overall. Women were two times more likely to experience nausea and twice as likely to experience severe nausea (statistical significance of p = .0001). In addition, persons with surgery lasting 2 hours or greater were twice as likely to experience nausea (statistical significance of p = .002). Independent nursing interventions, such as placing a cool washcloth on a patient's forehead, were used more often than medication as an initial strategy. The most frequently used interventions were increasing the i.v. fluids and having the patient take deep breaths. There was no pattern to the nursing assessments. CONCLUSION: Women and those patients with surgery lasting greater than 2 hours should be assessed for nausea in the postoperative period more frequently. Assessments need to be done during the first 2 hours after surgery, at 7-8 hours after surgery, and when there is an increase in activity, such as the first time out of bed. Nurses do not routinely document assessments for postoperative nausea. In addition, some misconceptions exist. Formal and informal education for nurses, physicians, and patients on the incidence, predisposing factors, and treatment options for postoperative nausea needs to occur. This should include reflection on the misconceptions, the need for ongoing patient assessment, and a review of drug and nondrug therapies. IMPLICATIONS FOR NURSING RESEARCH: Further research is needed to better describe the present practice patterns in the treatment of postoperative nausea and vomiting, including a comparison of inpatient and outpatient settings. The relative effectiveness of specific nursing interventions should be measured, such as i.v. fluids, deep breathing, and antiemetic use. In addition, the evaluation of the effectiveness of the use of a research protocol would be useful.

A survey of 636 staff nurses: perceptions and factors influencing the CNS role.

The specific aim of this investigation was to document the perceptions of the CNS role and the factors influencing the role. The Clifford Clinical Specialist Functions Inventory was used to survey staff nurses at two affiliated medical centers. A 38% response rate was obtained. A total of 636 surveys were returned. Analysis of the data indicated: the CNS was perceived as valuable; physical presence of the CNS on the nursing unit enhanced role enactment; and a list of CNS role expectations could be developed based on perceptions of staff nurses. The results indicated that perceptions of the CNS role did not vary among staff nurses at the two medical centers.

The clinical practice developmental model: the transition process.

The authors report their hospital's experience in replicating Benner's novice-to-expert clinical nursing practice model, called the Clinical Practice Developmental Model. The authors describe the outcomes of an exploratory, qualitative study conducted to understand staff nurses' perceptions of their transition experience from a traditional clinical ladder for advancement and recognition to the theoretically based clinical practice developmental model. The findings of this study identify critical factors that influenced nurses' perceptions and describe positive and negative outcomes of transition. Specific recommendations to facilitate organizational changes for the nurse executive and the individual nurse are discussed.