Small Time Differences Research Articles

Modelling of Human Low Frequency Sound Localization Acuity Demonstrates Dominance of Spatial Variation of Interaural Time Difference and Suggests Uniform Just-Noticeable Differences in Interaural Time Difference

Sound source localization is critical to animal survival and for identification of auditory objects. We investigated the acuity with which humans localize low frequency, pure tone sounds using timing differences between the ears. These small differences in time, known as interaural time differences or ITDs, are identified in a manner that allows localization acuity of around 1° at the midline. Acuity, a relative measure of localization ability, displays a non-linear variation as sound sources are positioned more laterally. All species studied localize sounds best at the midline and progressively worse as the sound is located out towards the side. To understand why sound localization displays this variation with azimuthal angle, we took a first-principles, systemic, analytical approach to model localization acuity. We calculated how ITDs vary with sound frequency, head size and sound source location for humans. This allowed us to model ITD variation for previously published experimental acuity data and determine the distribution of just-noticeable differences in ITD. Our results suggest that the best-fit model is one whereby just-noticeable differences in ITDs are identified with uniform or close to uniform sensitivity across the physiological range. We discuss how our results have several implications for neural ITD processing in different species as well as development of the auditory system.

Smartphone Traffic Engineering for Energy Efficient Communications: Design and Experimental Evaluation

Power management has increased its significance in mobile communications along with the growing population of mobile users and wireless connectivity. In this paper we propose a smart scheduling algorithm in Android network kernel to increase power efficiency. As periodically-updating applications start sync with a DNS query packet, we defer the packets in order to make these applications synchronize from smaller time difference to finally simultaneously. To implement the idea, we design the algorithm for two or more applications in this paper. This algorithm is composed of several mechanisms: approaching, aligning, and maintaining. By experiments we show the practicability and the comparison between the energy saving ratios in different scenarios.

Study of Some Lakes in the North-Eastern Romanian Plain Using the Coherence Image of the Tandem Pair (ERS-1 and ERS-2)

In radar SAR interferometry (InSAR/DinSAR), a Tandem pair (ERS-1/2) is used for the realization of a DEM or the detection of deformations of a major event (e.g. earthquake) occurring between two acquisitions. The advantage of the Tandem pair is the time interval of 24 hours between the two captures. Generally, there is no temporal decorrelation considering the small difference in time between the acquisitions, which results in a good coherence. The coherence image is used indirectly in radar SAR interferometry as an indicator of the levels of confidence of the interferograms. It can be used in a direct way to identify and delimit the various movement zones which disturb the phase of the radar wave. The objective of this work is to show the utility and the effectiveness of the coherence image in the cartography of lakes and vegetation in a region at the Curvature of the Romanian Carpathians1. Between the two acquisitions dates of May 28 and 29, 1995, there was no geological process involving displacements in direction of the radar. This pair represents the only one among the other pairs which gave a good coherence for the whole scene. In the flat part, one notes a good coherence except for the lakes. They are well represented by very dark colours with zero coherence. In the part of high altitude, especially where there is vegetation, a bad coherence can be clearly seen. Using this image (coherence), one could distinguish the parts with vegetation in great movements due to the effects of the wind, therefore characterised by great heights. The coherence image thus makes it possible to delimit two natural elements in this area, the lakes and the vegetation. The lakes are well delimited, in particular when they are full as in the rain seasons. To show this utility and this effectiveness of the coherence image, we measured the surfaces and dimensions of the lakes based on the Tandem pair and to make a comparison with the existing data and to interpret the results obtained. The three lakes, located in the plain to the East and North-East of the Buza;u town, clearly appear in the coherence image.

Effects of Plyometric Training on Endurance and Explosive Strength Performance in Competitive Middle- and Long-Distance Runners

The purpose of this study was to examine the effect of a short-term plyometric training program on explosive strength and endurance performance in highly competitive middle- and long-distance runners. Athletes were randomly assigned to a control group (CG, n = 18, 12 men) and an explosive strength training group (TG, n = 18, 10 men). Drop jump (DJ) from 20 (DJ20) and 40 cm (DJ40), countermovement jump with arms (CMJA), 20-m sprint time, and 2.4-km endurance run time test were carried out before and after 6 weeks of explosive strength training. Also, the combined standardized performance (CSP) in the endurance and explosive strength test was analyzed. After intervention, the CG did not show any significant change in performance, whereas the TG showed a significant reduction in 2.4-km endurance run time (-3.9%) and 20-m sprint time (-2.3%) and an increase in CMJA (+8.9%), DJ20 (+12.7%), and DJ40 (16.7%) explosive performance. Strength training group also exhibited a significant increase in CSP, although the CG showed significant reduction. We conclude that properly programmed concurrent explosive strength and endurance training could be advantageous for middle- and long-distance runners in their competitive performance, especially in events characterized by sprinting actions with small time differences at the end of the race.

Investigations into the locus of language-switching costs in older adult bilinguals

Language switching was studied with older adult (age 65 years and older) and young adult (18–24 years) bilinguals in a blocked-language or mixed-language condition. Results revealed small differences in reaction time (RT) between older adults and college-age participants in the blocked condition. However, older adults showed much slower RTs in the mixed condition which involves sustained switching relative to young adults. In Experiment 2, the same design was used except that participants were asked to translate an auditory word. In this condition, older adults showed a slowing effect but to a much lesser degree. Furthermore, comparisons within the mixed condition (transient switching) revealed that switching costs varied across languages and age groups. The results from the picture-naming task are consistent with models that predict deficiencies in task-set shifting in older adults especially when a stimulus activates multiple responses. Furthermore, the results indicate interesting differences in sustained and transient switching depending on the task.

Detection of submillisecond spike timing differences based on delay-line anticoincidence detection

Detection of submillisecond interaural timing differences is the basis for sound localization in reptiles, birds, and mammals. Although comparative studies reveal that different neural circuits underlie this ability, they also highlight common solutions to an inherent challenge: processing information on timescales shorter than an action potential. Discrimination of small timing differences is also important for species recognition during communication among mormyrid electric fishes. These fishes generate a species-specific electric organ discharge (EOD) that is encoded into submillisecond-to-millisecond timing differences between receptors. Small, adendritic neurons (small cells) in the midbrain are thought to analyze EOD waveform by comparing these differences in spike timing, but direct recordings from small cells have been technically challenging. In the present study we use a fluorescent labeling technique to obtain visually guided extracellular recordings from individual small cell axons. We demonstrate that small cells receive 1-2 excitatory inputs from 1 or more receptive fields with latencies that vary by over 10 ms. This wide range of excitatory latencies is likely due to axonal delay lines, as suggested by a previous anatomic study. We also show that inhibition of small cells from a calyx synapse shapes stimulus responses in two ways: through tonic inhibition that reduces spontaneous activity and through precisely timed, stimulus-driven, feed-forward inhibition. Our results reveal a novel delay-line anticoincidence detection mechanism for processing submillisecond timing differences, in which excitatory delay lines and precisely timed inhibition convert a temporal code into a population code.

Mapping the radio sky with an interferometric network of low‐frequency radio receivers

The structure of the 100 kHz radio sky is determined with two interferometric networks of 10 radio receivers which are distributed over local areas of ∼1 × 1 km2 and ∼10 × 10 km2. The radio waves arrive at individual receiver pairs with small time differences which are used to determine the arrival direction of the electromagnetic waves including both the bearing and the elevation angle. The results show that the major part of the 100 kHz radio wave energy comes from the horizon at bearings which are consistent with known locations of Long Range Navigation (LORAN) transmitters. Some part of the radio wave energy arrives from the sky at elevation angles which are consistent with the first and second sky hop waves of LORAN transmissions. A minor part of the 100 kHz radio wave energy comes from lightning discharges at distances up to ∼1000 km with bearings which are consistent with lightning locations reported by the arrival time difference (ATD) lightning detection network of the UK Met Office. The angular resolution for mapping the radio sky depends on the network geometry, the instrumental timing accuracy, and on the signal‐to‐noise ratio of the radio waves. The resulting angular resolution of the interferometric networks used in this study is ∼1° in bearing at zero elevation and several degrees in elevation.

The association of race with timeliness of care and survival among Veterans Affairs health care system patients with late-stage non-small cell lung cancer

BackgroundNon-small cell lung cancer is the leading cause of cancer-related mortality in the United States. Patients with late-stage disease (stage 3/4) have five-year survival rates of 2%–15%. Care quality may be measured as time to receiving recommended care and, ultimately, survival. This study examined the association between race and receipt of timely non-small cell lung cancer care and survival among Veterans Affairs health care system patients.MethodsData were from the External Peer Review Program, a nationwide Veterans Affairs quality-monitoring program. We included Caucasian or African American patients with pathologically confirmed late-stage non-small cell lung cancer in 2006 and 2007. We examined three quality measures: time from diagnosis to (1) treatment initiation, (2) palliative care or hospice referral, and (3) death. Unadjusted analyses used log-rank and Wilcoxon tests. Adjusted analyses used Cox proportional hazard models.ResultsAfter controlling for patient and disease characteristics using Cox regression, there were no racial differences in time to initiation of treatment (72 days for African American versus 65 days for Caucasian patients, hazard ratio 1.04, P = 0.80) or palliative care or hospice referral (129 days versus 116 days, hazard ratio 1.10, P = 0.34). However, the adjusted model found longer survival for African American patients than for Caucasian patients (133 days versus 117 days, hazard ratio 0.31, P < 0.01).ConclusionFor process measures of care quality (eg, time to initiation of treatment and referral to supportive care) the Veterans Affairs health care system provides racially equitable care. The small racial difference in survival time of approximately 2 weeks is not clinically meaningful. Future work should validate this possible trend prospectively, with longer periods of follow-up, in other veteran groups.

Relation between perceived direction of a sound image and the behavior of the precedence effect

When similar sounds come to a listener from two different directions with the same level and small time difference (0–2ms), he/she perceives a single sound image and its position changes from the middle of two sound sources for no time difference between two sounds to the direction of the leading sound with increasing time difference. This phenomenon is well known as a change from the summing localization to the precedence effect, but the process for such a change has not been sufficiently elucidated. In order to make use of the precedence effect for designing a public address system, the effect needs to be quantified.In this paper, we describe two hearing experiments carried out with the same subjects and conditions. We then analyzed the relation between the perception of a sound image and the behavior of the summing localization and the precedence effect. The difference between two experiments was in the instruction that the subjects were asked to answer. The instruction in the first experiment was the perceived direction of the sound image, while in the second experiment the instruction was the position of the sound source nearest to the perceived sound image. The boundary time difference separating the summing localization from the localization based on the precedence effect was calculated from the results of both experiments. Consequently we found that: (a) the absolute value of the boundary time difference varies in the range of 0.4–0.8ms with the small level difference (0,+3dB) between two sound sources and (b) the perceived image at the boundary time difference is localized around 10° from the left/right-side sound source to the middle of two sound sources.

Validation of a New Method to Measure Contact and Flight Times During Treadmill Running

The purpose of this study was to validate a new method to measure contact and flight times during treadmill running and to test its reliability and sensitivity. Fifteen well-trained runners performed 7 sets of running at different speeds (from 10 to 22 km·h). Contact and flight times were simultaneously recorded by a high-speed video system (gold standard method) and a new method based on laser technology (SportJump System Pro). Athletes were classified according to their foot strike pattern (rearfoot vs. midfoot and forefoot). The new method overestimated the contact time and underestimated the flight time with respect to the gold standard method (p < 0.001). However, relationships and intraclass correlation coefficients (ICCs) between both systems were very strong (r and ICC > 0.99, p < 0.001). Contact time differences between the 2 systems depended on running speed (p < 0.001) but not on foot strike pattern or runners' body mass. This allowed to correct the differences in contact time and flight time. The new method was sensitive for detecting small differences in contact time (<20 ms) when the running speed increased and when the type of foot strike patterns changed. Additionally, a low intraindividual step variability (coefficient of variation = 2.0 ± 0.5%) and high intra- (ICC = 0.998) and interobserver (ICC = 0.977) reliability were shown. In conclusion, the new method was validated, being reliable and sensitive for detecting small differences in contact and flight times during treadmill running. Therefore, it could be used to compare biomechanical variables between groups in cross-sectional studies and to verify the influence of some independent variables (i.e., training, running economy, or performance) on running biomechanics.

Unusual Mortality Events of Harbor Porpoise Strandings in North Carolina, 1997–2009

A marked increase in the frequency of harbor porpoises (Phocoena phocoena) stranded in North Carolina in 2005 was declared as an Unusual Mortality Event (UME). Strandings occurred in January through May when harbor porpoises are seasonally present. Increased stranding rates were measured relative to a threshold to determine that the UME was occurring. The threshold analysis also revealed elevated strandings during 1999, an undeclared UME year. Recovered carcasses during 1999 and 2005 accounted for 39% of 261 strandings during 1997–2009. During 2005, of 43 strandings, primary or secondary causes of mortality included fishery interactions, emaciation, and interspecific aggression. Apart from small but significant differences in timing and condition of strandings, composition of strandings during UME and non-UME years was similar, with most being young-of-the-year and occurring during March and April, north of Cape Hatteras. Porpoises had high levels of parasitic infestation typical for this species. However, no indication of infectious disease and no cause of the 2005 event were found from gross and histologic findings. Response to UMEs is challenging, particularly along the expanses of North Carolina beaches, requiring additional effort to obtain carcasses in sufficiently fresh condition to determine the cause of these events.

Monitoring Bridge Deformation Using Auto-Correlation Adjustment Technique for Total Station Observations

Bridges are omnipresent in every society and they affect its human, social, ecological, economical and cultural aspects. This is why a durable and safe usage of bridges is an imperative goal of structural management. Measurement and monitoring have an essential role in structural management. The benefits of the information obtained by monitoring are apparent in several domains. In deformation analysis, the functional relationship between the acting forces and the resulting deformations should be established. If time depending observations are given, a regression could be used as a functional model. In case of stochastic model uncorrelated observations with identical variance are assumed. Due to the high sampling rate, a small time difference arises between two observations. Thus the assumed stochastic model is not suitable. The calculation has to be effected by means of auto-correlated observations. This paper investigates an integrated monitoring system for the estimation of the deformation (i.e., static, quasi-static) behavior of bridges from total station observations and studies the effect of autocorrelation technique on the accuracy of the estimated parameters and variances. The results have shown that autocorrelation technique is reduced the standard deviation of X&Y-direction about 6.7% to 29.4% and 6.5% to 15.5% of the original value, respectively, but the situation was differ in Z direction; the standard deviation in vertical component Z was increased.

Asymmetric neurotransmitter release enables rapid odour lateralization in Drosophila

In Drosophila, most individual olfactory receptor neurons (ORNs) project bilaterally to both sides of the brain1,2. Having bilateral rather than unilateral projections may represent a useful redundancy. However, bilateral ORN projections to the brain should also compromise the ability to lateralize odors. Nevertheless, walking or flying Drosophila reportedly turn toward their more strongly stimulated antenna3-5. Here we show that each ORN spike releases ~40% more neurotransmitter from the axon branch ipsilateral to the soma, as compared to the contralateral branch. As a result, when an odor activates the antennae asymmetrically, ipsilateral central neurons begin to spike a few milliseconds before contralateral neurons, and ipsilateral central neurons also fire at a 30-50% higher rate. We show that a walking fly can detect a 5% asymmetry in total ORN input to its left and right antennal lobes, and can turn toward the odor in less time than it requires the fly to complete a stride. These results demonstrate that neurotransmitter release properties can be tuned independently at output synapses formed by a single axon onto two target cells with identical functions and morphologies. Our data also show that small differences in spike timing and spike rate can produce reliable differences in olfactory behavior.

Activation of metabotropic glutamate receptors improves the accuracy of coincidence detection by presynaptic mechanisms in the nucleus laminaris of the chick

Interaural time difference (ITD) is a major cue for localizing a sound source and is processed in the nucleus laminaris (NL) in birds. Coincidence detection (CD) is a crucial step for processing ITD and critically depends on the size and time course of excitatory postsynaptic potentials (EPSPs). Here, we investigated a role of metabotropic glutamate receptors (mGluRs) in the regulation of EPSP amplitude and CD in the NL of chicks. A non-specific agonist of mGluRs ((±)-1-aminocyclopentane-trans-1,3-dicarboxylic acid; t-ACPD) reduced the amplitude and extent of depression of excitatory postsynaptic currents (EPSCs) during a stimulus train, while the paired pulse ratio and coefficient of variation of EPSC amplitude were increased. In contrast, the amplitudes of spontaneous EPSCs were not affected, but the frequency was reduced. Thus, the effects of t-ACPD were presynaptic and reduced the release of neurotransmitter from terminals in the NL. Expression of group II mGluRs was graded along the tonotopic axis and was stronger towards the low frequency region in the NL. Both group II (DCG-IV) and group III (l-AP4) specific agonists reduced EPSC amplitude by presynaptic mechanisms, and the reduction was larger in the low frequency region; however, we could not find any effects of group I-specific agonists on EPSCs. The reduced EPSP amplitude in DCG-IV improved CD. A specific antagonist of group II mGluRs (LY341495) increased the amplitude of both EPSCs and EPSPs and enhanced the depression during a stimulus train, indicating constitutive activation of mGluRs in the NL. These observations indicate that mGluRs may work as autoreceptors and regulate EPSP size to improve CD in the NL.

Azimuthal sound localization in the European starling (Sturnus vulgaris): II. Psychophysical results

Small songbirds have a difficult analysis problem: their head is small compared to the wavelengths of sounds used for communication providing only small interaural time and level differences. Klump and Larsen (1992) measured the physical binaural cues in the European starling (Sturnus vulgaris) that allow the comparison of acoustical cues and perception. We determined the starling's minimum audible angle (MAA) in an operant Go/NoGo procedure for different spectral and temporal stimulus conditions. The MAA for broadband noise with closed-loop localization reached 17°, while the starling's MAA for open-loop localization of broadband noise reached 29°. No substantial difference between open-loop and closed-loop localization was found in 2 kHz pure tones. The closed-loop MAA improved from 26° to 19° with an increase in pure tone frequency from 1 to 4 kHz. This finding is in line with the physical cues available. While the starlings can only make use of interaural time difference cues at lower frequencies (e.g., 1 and 2 kHz), additional interaural level difference cues become available at higher frequencies (e.g., 4 kHz or higher, Klump and Larsen 1992). An improvement of the starling's MAA with an increasing number of standard stimulus presentations prior to the test stimulus has important implications for determining relative (MAA) localization thresholds.

A Risk-Adapted Protocol for Delayed Administration of Filgrastim After High-Dose Chemotherapy and Autologous Stem Cell Transplantation

The routine use of recombinant human granulocyte-colony stimulating factor (rhG-CSF) after high-dose chemotherapy and autologous stem cell transplantation (auto-SCT) is associated with increased costs. We prospectively explored a strategy that used prophylactic delayed filgrastim only in patients with risk factors. This sequential cohort analysis compared the outcomes of consecutive patients, treated on the risk-adapted protocol (RAP) (risk factors: prior febrile neutropenia; age >60 years; and CD34+ cell infused dose of <2 × 10(6/)/kg), who received filgrastim from day +6 after auto-SCT with a historical cohort (historical day-1 cohort [HD1]), who received filgrastim from day +1. Eighty-two patients were treated in the RAP cohort and compared with 115 patients in the HD1 cohort. There were no differences in median age (55 years) or median CD34+ cell dose (5.21 × 10(6)/kg [range, 2-62.2 × 10(6)/kg] vs. 5.24 × 10(6)/kg [range, 2.4-29.8 × 10(6)/kg]). Filgrastim was used for 6 fewer days in the RAP cohort (median 5 days [range, 0-11 days] vs. 11 days [range, 9-47 days]). There was a small absolute but significant difference in median time to neutrophil recovery in the HD1 cohort for the whole group, 10 days (range, 8-46 days) vs. 11 days (range, 9-22 days) (P = .03) and in patients with myeloma; 10 days (range, 9-14 days) vs. 11 days (range, 9-18 days) (P < .0001) as compared to the RAP cohort. There was no difference in median inpatient duration, 13 days (range, 10-26 days) vs. 12 days (range, 1-38 days) (P = .22) and 3-year survival (79% vs. 83% [P = .43]) between HD1 and RAP cohorts respectively. The use of a RAP to identify patients likely to benefit from prophylactic filgrastim is safe and results in cost savings. Patients with myeloma benefit from earlier introduction of filgrastim in terms of neutrophil recovery; this disease-specific observation is an important consideration for future studies.

Multimodality Imaging of Lower Extremity Peripheral Arterial Disease

Patients with symptomatic peripheral arterial disease (PAD) affecting the lower extremities are initially evaluated with an ankle-brachial index (ABI) and segmental pressure measurements. An ABI 50% stenosis) with a sensitivity and specificity of 79% and 96%, respectively.1 An ABI between 0.90 and 1.0 is considered borderline. The localization of the stenosis can be inferred by an abnormal decrease (>20 mm Hg) in segmental lower extremity pressures. In the presence of calcified atherosclerosis, arteries may become stiff and noncompressible, which results in a falsely elevated ABI (often >1.3). For patients with suspected PAD and a normal ABI at rest, it is valuable to obtain postexercise ABI measurements, which if <0.85 are consistent with PAD and is an independent predictor of mortality.2 Imaging is then needed to confirm the location and degree of stenosis before revascularization or if the diagnosis of PAD is uncertain. Characterization of PAD can be performed with noninvasive angiography using computed tomography (CTA) or magnetic resonance angiography (MRA), as well as with duplex ultrasonography (US), depending on patient specific characteristics (Table 1). Advances in both CTA and MRA provide clinicians with the opportunity to obtain a high resolution, 3-dimensional (3-D) road map of the peripheral arterial tree in patients, particularly when planning revascularization strategies. Invasive digital subtraction angiography (DSA) has been the accepted standard for evaluation of lower extremity atherosclerosis. Although DSA is a robust technique for diagnosing significant arterial stenosis or obstruction, it provides a 2-D view of the vessels, which may underestimate the degree of stenosis for tortuous vessels.3 Furthermore, there are inherent risks with arterial access, ionizing radiation, and the use of iodinated contrast media (CM).4 View this table: Table 1. Comparison Between CTA, MRA, and Duplex US for Diagnosis of PAD This review aims to deliver a comprehensive, yet concise …

Measuring relative timings of brain activities using fMRI

Functional MRI (fMRI) has previously been shown to be able to measure hundreds of milliseconds differences in timings of activities in different brain regions, even though the underlying blood oxygenation level-dependent (BOLD) response is delayed and dispersed on the order of seconds. This capability may contribute towards the study of communication within the brain by assessing the temporal sequences of various brain processes (mental chronometry). The practical limit of fMRI for detecting the relative timing of brain activity is not known. We aimed to detect fine differences in the timings of brain activities beyond those previously measured from fMRI data in human subjects. We introduced known delays between the onsets of visual stimuli in a controlled, sparse event-related design and investigated if the temporal shifts in the corresponding average BOLD signals were detectable. To maximize sensitivity, we used high spatial and temporal resolution fMRI at ultrahigh field (7 T), in conjunction with a novel data-driven technique for voxel selection using graph-based visualizations of self-organizing maps and Granger causality to measure relative timing. This approach detected timing differences as small as 28ms in visual cortex in individual subjects. For signal extraction, the self-organizing map approach outperformed other common techniques including independent component analysis, voxelwise univariate linear regression analysis and a separate localizer scan. For relative timing measurement, Granger causality outperformed time-to-peak calculations derived from an inverse logit curve fit. We conclude that high-resolution imaging at ultrahigh field, signal extraction via self-organizing map, and appropriate use of Granger causality permit the detection of small timing differences in fMRI data, despite the intrinsically slow hemodynamic response.

Role of Capsule Study in Evaluation of Irritable Bowel Syndrome

Purpose: Introduction: Irritable bowel syndrome (IBS) is a common disorder that accounts for one-third of the referrals to a gastroenterologist. Most patients diagnosed with IBS have had limited or no evaluation for pathology of the small bowel or for presence of abnormal transit time. Capsule endoscopy is a non-invasive method of imaging the small bowel and measuring transit time. The purpose of this study is to measure the prevalence of small bowel mucosal pathology in diarrhea dominant or mixed bowel pattern IBS patient and to measure differences in transit time. Methods: Prospective study participants at Naval Medical Center Portsmouth qualified for Rome III criteria of diarrhea and mixed type IBS and had no alarm symptoms. Each patient underwent capsule study and images were evaluated by a gastroenterologist. Gastric transit time and small bowel transit time were determined by landmark identification using the GIVENTM capsule system. Post-hoc analysis was performed for transit time differences and two-tailed paired t-test was performed. P-values were determined using two tails. Results: 20 of the patients enrolled were alternating types and 30 were diarrhea dominant types. Two diarrhea types were excluded from study final transit time results, one due to obscured camera view and the other secondary to the capsule being inserted below the pylorus by endoscopy. No small bowel pathology was found in all patients. The mean gastric transit time for the alternating type was 46.9 minutes (SD 42.21) and for the diarrhea dominant type was 46.75 minutes (SD 50.94), P =0.9914. The mean for small bowel transit time was 261.9 minutes (SD 89.33) for alternating type and 178.21 minutes (SD 70.87) for diarrhea dominant type, P=0.0007. Conclusion: No small bowel pathology was found in all IBS patients and supports ACG position statement concerning evaluation of IBS patients. However, capsule endoscopy was able to document statistically significant small bowel transit time differences between IBS patients who had diarrhea predominate symptoms and alternating predominate symptoms. The use of capsule technology may help direct medical management in complex IBS patients.

Impact of rocuronium vs succinylcholine neuromuscular blocking drug choice for laparoscopic pyloromyotomy: is there a difference in time to transport to recovery?

This study evaluates the relationship between neuromuscular blocking drug administered and transport time following laparoscopic pyloromyotomy. Infants with pyloric stenosis have indication for rapid sequence induction. While succinylcholine has rapid onset and short duration, its use in children may be associated with rare serious adverse effects. Rocuronium is a widely accepted alternative, but its duration could contribute to delay at surgery end. Infants undergoing laparoscopic pyloromyotomy at Loma Linda University Medical Center Children's Hospital from January 2006 to July 2011 were studied retrospectively. Only term infants receiving propofol induction, sevoflurane maintenance, no intraoperative opioid, and rocuronium, succinylcholine, or both were included. The primary outcome measure was time to transport after surgery stop as a measure of recovery from both anesthesia and relaxant. Data was analyzed for relationships between drug choice and time to transport. Data from 246 patients was analyzed. Patients were similar in all groups. Time to transport was not affected by doses of propofol or neuromuscular blocking drug, anesthesia to surgery end interval or surgery length. Time to transport (minutes median, interquartile range) was 13 (7-21) in patients receiving only succinylcholine compared to 18 (11-24) in those receiving only rocuronium (P=0.03). For laparoscopic pyloromyotomy in term infants using propofol, sevoflurane and no intraoperative opioid, succinylcholine may be the best neuromuscular blocking drug choice, provided no contraindication is present. However, based on the small difference in time to transport, rocuronium as administered herein may be a reasonable alternative preferred by some clinicians.