Paired Comparison Study Research Articles

Head-only followed by cardiac arrest electrical stunning is an effective alternative to head-only electrical stunning in pigs1

Many small slaughter facilities use head-only electrical stunning to render swine unconscious and insensible to pain before slaughter. Head-only electrical stunning is a reversible procedure that is optimally effective for approximately 15 s after stun completion. In many small North American slaughter plants, the authors have observed hoist speeds that are too slow to achieve a short enough stun-to-bleed interval to maintain insensibility through exsanguination. Unlike many European plants, there is no separate high-speed hoist for pigs and exsanguination on the floor is not condoned. As a result, a 2-stage stunning method was proposed where head-only stunning for 3 s was immediately followed by application of the same stunning wand to the cardiac region of the animal for 3 s while lying in lateral recumbancy. A paired-comparison study was conducted on 89 pigs in a small slaughter facility to compare the head-only method applied for 6 s with the head/heart method. The objective was to evaluate signs of return to sensibility, stun-to-bleed time, blood lactate concentration, muscle pH, drip loss, and fresh meat color to validate the head/heart electrical stunning method for small slaughter plants. Incidence of corneal reflex was not different (P > 0.05) between head/heart (93.8%) and head only (85%) stunning. Nose twitching was more common (P < 0.05) in head only (26.5%) than head/heart (5%) stunning. Head/heart stunning eliminated rhythmic breathing, natural blinking, eye tracking to moving objects, and righting reflex, which were all observed in head-only stunned pigs. Eye tracking to moving objects was observed in 40.8% of head-only stunned pigs. Blood lactate was not different (P > 0.05) between stunning methods (head only: 8.8 ± 0.7 mmol/L, head/heart: 7.8 ± 0.7 mmol/L). Stun-to-bleed time did not differ (P > 0.05; head only: 32 ± 1 s, head/heart: 33 ± 1 s). Mean time to loss of heartbeat with the head-only method was 121 ± 5 s. No heartbeat was observed with the head/heart method. Longissimus thoracis pH, color, and drip loss were not different (P > 0.05) between stunning methods. This study determined that the head/heart electrical stunning method reduces the incidence of signs of return to sensibility without significant effects on meat quality, plant operation speed, or blood lactate concentration. In addition, the head/heart method requires no capital investment for plants that are currently using the head-only method.

Proteome Mining of Human Follicular Fluid Reveals a Crucial Role of Complement Cascade and Key Biological Pathways in Women Undergoing in Vitro Fertilization

In vitro fertilization (IVF) is fraught with problems and currently proteomics approaches are being tried out to examine the microenvironment of the follicle in order to assess biological and immunological parameters that may affect its development. Additionally, better understanding of reproductive process may help increase IVF birth rate per embryo transfer and at the same time avoid spontaneous miscarriages or life threatening conditions such as ovarian hyperstimulation syndrome. The primary aim of this study was to search for specific differences in protein composition of human follicular fluid (HFF) and plasma in order to identify proteins that accumulate or are absent in HFF. Depletion of abundant proteins combined with multidimensional protein fractionation allowed the study of middle- and lower-abundance proteins. Paired comparison study examining HFF with plasma/serum from women undergoing successful IVF revealed important differences in the protein composition which may improve our knowledge of the follicular microenvironment and its biological role. This study showed involvement of innate immune function of complement cascade in HFF. Complement inhibition and the presence of C-terminal fragment of perlecan suggested possible links to angiogenesis which is a vital process in folliculogenesis and placental development. Differences in proteins associated with blood coagulation were also found in the follicular milieu. Several specific proteins were observed, many of which have not yet been associated with follicle/oocyte maturation. These proteins together with their regulatory pathways may play a vital role in the reproductive process.

Comparison of a PACS Workstation with Laser Hard Copies for Detecting Scaphoid Fractures in the Emergency Department

Picture archiving and communication systems (PACS) for imaging studies is rapidly being adopted in hospitals throughout the UK. However, very little comparison has been made between PACS and laser hard copies for assessing the diagnostic accuracy of detecting fractures by emergency physicians. A prospective paired comparison study was undertaken looking at correct reporting of scaphoid X-rays on PACS and conventional film by emergency department medical staff. A total of 34 imaging studies were reported by 38 physicians using both PACS workstations and laser-printed films. The percentage of emergency physicians correctly reporting imaging studies was similar when comparing PACS images to laser film copies (80.7% versus 81.0%). The sensitivity and specificity of PACS for diagnosing scaphoid fractures was 79.5% and 81.6%, versus 78.1% and 83.8% for conventional films. There is no significant difference in accuracy of diagnosis between PACS and laser film copies when scaphoid X-rays are reported by emergency physicians.

Explaining Civil-Military Relations in Complex Political Environments: India and Pakistan in Comparative Perspective

This article argues that military intervention into politics can only be understood by studying both the nature of threats and of domestic political arrangements. I offer a theory of the military in politics built around the interaction between threat configuration, political institutionalization, and civilian government legitimacy. The argument is tested with paired-comparison case studies of Indian and Pakistani civil-military relations since independence. Despite their similarities at the time of partition, these two militaries took completely different political trajectories. The cases reveal how structures of domestic politics interact with military threat perceptions to explain civilians' ability to maintain varying levels of control over the military.

Applications of psychoacoustics to information technology products

Emerging usage models for computing devices require low acoustic noise, for example in home entertainment systems. Studies have shown that not only the overall level, but also the psychoacoustic aspects matter. This paper provides an overview of testing techniques that are used in the information technology industry and outlines two specific case studies. First, an extensive subjective psychoacoustic study was designed and conducted in multiple geographies to determine the aspects of sound that best describe the annoyance to sound from information technology products in a home type environment. Over 200 participants in four countries participated in this carefully controlled experiment and rated typical steady state sounds on a 5 point annoyance scale. The relevant sound quality metrics were extracted and geographical variations quantified. Second, in a paired comparison study the influence of modulation on annoyance was investigated by superimposing different frequency and amplitude modulated sounds onto a baseline sound. The results indicate that modulation can have a significant effect on subjective perception.

The short pulse carbon dioxide laser versus the colorado needle tip with electrocautery for upper and lower eyelid blepharoplasty

Various techniques for blepharoplasty have been described, including those performed with the assistance of the short pulse carbon dioxide laser and those performed with the assistance of the Colorado microdissection needle attached to an electrocautery unit. Although the superiority of the carbon dioxide laser to cold steel has been demonstrated for the performance of eyelid blepharoplasty, no studies have ever compared the carbon dioxide laser to the Colorado needle. This is a paired comparison study in which 12 healthy patients underwent bilateral blepharoplasty of their upper and/or lower eyelids by a single surgeon. For each patient, a short pulse carbon dioxide laser was used on one side, and a Colorado needle attached to an electrocautery unit was used on the other. Intraoperative times were recorded. At five post-operative visits patients were evaluated for post-operative healing parameters including edema, erythema, scar width, and bruising. Finally, excised tissue was assessed histologically for thermal damage. Comparing both techniques, no difference in patient or physician-measured parameters of healing were noted up to 1 month post-operatively. However, Colorado needle assisted blepharoplasty resulted in slightly shorter intraoperative times. It also resulted in less thermal damage on a histologic level, although these differences were not clinically significant. For the performance of blepharoplasty, the Colorado needle tip with electrocautery offers benefits equivalent to those of the short pulsed CO2 laser but has the advantage of shorter intraoperative times and lower cost.

A Randomized, Evaluator-Blinded, Two-Center Study of the Safety and Effect of Volume on the Diffusion and Efficacy of Botulinum Toxin Type A in the Treatment of Lateral Orbital Rhytides

BACKGROUND There has been considerable discussion about the effect of the degree of dilution of botulinum toxin (BTX) but very few scientific studies. OBJECTIVE The objective was to observe as to whether a fivefold difference in concentration of BTX solution would produce a difference in clinical effect or duration of effect. METHODS AND MATERIALS Twenty individuals were enrolled at two sites and a within-subject paired-comparison study was performed on the lateral orbital area with a single injection of 5 U of BTX (BOTOX Cosmetic, Allergan Inc., Irvine, CA). The results were assessed both clinically and using a computer-assisted estimation of the degree of wrinkling. RESULTS No statistically significant differences were observed between the two sides. CONCLUSIONS This is a small study and it may be that dilution does affect BTX result. We were, however, unable to detect any difference in this study, which suggests that the degree of dilution, at least within a fivefold margin, has only a small effect on the results of BTX injection in the lateral orbital area.

A Randomized, Evaluator-Blinded, Two-Center Study of the Safety and Effect of Volume on the Diffusion and Efficacy of Botulinum Toxin Type A in the Treatment of Lateral Orbital Rhytides

There has been considerable discussion about the effect of the degree of dilution of botulinum toxin (BTX) but very few scientific studies. The objective was to observe as to whether a fivefold difference in concentration of BTX solution would produce a difference in clinical effect or duration of effect. Twenty individuals were enrolled at two sites and a within-subject paired-comparison study was performed on the lateral orbital area with a single injection of 5 U of BTX (BOTOX Cosmetic, Allergan Inc., Irvine, CA). The results were assessed both clinically and using a computer-assisted estimation of the degree of wrinkling. No statistically significant differences were observed between the two sides. This is a small study and it may be that dilution does affect BTX result. We were, however, unable to detect any difference in this study, which suggests that the degree of dilution, at least within a fivefold margin, has only a small effect on the results of BTX injection in the lateral orbital area.

P-779: Differentially decreased ovarian response to controlled ovarian hyperstimulation in patients with unilateral endometriomas

A growing body of data clearly associates ovarian endometriosis with decreased ovarian response to controlled ovarian hyperstimulation (COH). Surgical removal of ovarian endometriomas (OE) have failed to improve ovarian responsiveness to subsequent COH, suggesting that directly proceeding to COH in asymptomatic women decreases time to pregnancy and potential complications of surgery. However, it is unclear whether this decreased ovarian reserve is a systemic effect of endometriosis or a localized reaction caused by the genesis of OE. This study aims to address this issue by comparing COH responses between ovaries in women with one normal and one endometrioma-affected ovary. Paired-comparison study. Patients with unilateral endometriomas on transvaginal ultrasound ranging from 1 to 4cm in diameter and undergoing COH were identified from January 2005 to March 2006. The diagnosis by transvaginal ultrasonography was made with evidence of well-accepted criteria for OE. The inclusion criteria were women <37 years of age with regular 27-35 day menstrual cycles. Excluded were patients with PCOS, poor response to previous COH cycles, history of ovarian surgeries, autoimmune diseases, systemic therapies for cancer, and smokers. A total of 41 patients fulfilled the inclusion and exclusion criteria. All patients received oral contraception suppression to LH<4 mIU/ml, E2<50 pg/ml, and follicular diameters <4mm prior to therapy. Ovarian hyperstimulation was achived with either 150 or 225 IU of recombinant FSH daily to reach stimulation values of FSH>12 mIU/ml. The mean number of dominant follicles ≥16mm produced by the OE ovaries on the day of HCG administration was calculated; this was compared to the mean number of follicles produced by the normal, contralateral ovaries using a Wilcoxon Signed-Ranks test for matched pairs. The subjects’ age ranged from 25 to 37 years old (mean 32.6 ± 3.3 years) and had unilateral endometriomas with mean size of 2.8 ± 0.5 cm. Their mean starting FSH and E2 values were 5.5 ± 2.1 mIU/ml and 33.4 ± 14.1 pg/ml, respectively. The mean FSH after stimulation and peak E2 levels were 14.3 ± 4.4 mIU/ml and 1240.9 ± 772.2 pg/ml. The mean number of follicles produced by a normal ovary undergoing COH was 4.0 ± 2.3, and the mean number of follicles produced by the contralateral, endometrioma-affected ovary was found to be significantly lower at 2.5 ± 1.4 (p<0.0002; 95% CI -2.18 to -0.89). Of the diseased ovaries, 7.3% (3/41) had no dominant follicles at all, where as none of the normal ovaries failed to produce any follicles. In 73% (30/41) of the subjects, there was significant incongruity in follicular development, where the normal ovary produced ≥50% more follicles than the OE ovary. The size of an endometrioma had no linear relationship to either the number of follicles produced or the incongruity ratio of follicular development between the two ovaries. The results suggest that ovaries affected by even a small endometrioma have significantly decreased production of dominant follicles when compared to their normal counterparts under superovulation with gonadotropins. Furthermore, it appears this impaired ovarian response is differentially related to the localized effects present in the endometrioma-affected ovary and may be related to the multiple factors included in the genesis of the endometrioma.

Site-specific skin reactions to amethocaine

To identify the incidence of children who have local reactions to amethocaine and whether site and age are important factors in the occurrence of local reactions. A within group (paired) comparison study. Children attending an outpatient department for venepuncture as part of their normal treatment had amethocaine applied to the elbow and the dorsum of the hand. Seventy-seven children took part in the study of whom 42 (55 per cent) had an urticarial reaction. All 42 children with an urticarial reaction experienced the reaction at the elbow, four of these children also had a reaction at the dorsum of the hand. There was an association between age and reaction with the frequency of reaction greater in younger children (p=0.0002). There is an increased frequency of urticarial reaction when amethocaine is used at the elbow compared with the dorsum of the hand. Younger children are at an increased risk of experiencing a reaction.

Exploratory Analysis of Crossing Difficulties for Blind and Sighted Pedestrians at Channelized Turn Lanes

This paper presents the findings from a paired comparison study of blind and sighted pedestrians judging crossing opportunities in traffic from the roadside at three channelized turn lane (CTL) locations. It is motivated by the belief that the geometric nature of CTL facilities and the lack of signal control at the pedestrian crossing are factors that may negatively affect the delay and safety for blind pedestrians. Pedestrians waiting at the curb must judge the traffic moving in a circular motion, and they must deal with a significant amount of background traffic (i.e., noise) present at the main intersection. The findings show that crossings at all CTL crossing locations are significantly more difficult for blind pedestrians than for sighted pedestrians. Blind pedestrians tend to face a greater risk and a greater amount of delay. Furthermore, the research shows that conflicting traffic flow in the turn lane has a significant effect on crossing performance for both pedestrian groups; however, the effect of noise-generating background traffic on blind pedestrian crossings is not significant. The study also concludes that for this experiment the location of the crosswalk (in the center of the turn lane or at the downstream end) does not have a significant effect on crossing judgment performance.

Exploratory Analysis of Crossing Difficulties for Blind and Sighted Pedestrians at Channelized Turn Lanes

This paper presents the findings from a paired comparison study of blind and sighted pedestrians judging crossing opportunities in traffic from the roadside at three channelized turn lane (CTL) locations. It is motivated by the belief that the geometric nature of CTL facilities and the lack of signal control at the pedestrian crossing are factors that may negatively affect the delay and safety for blind pedestrians. Pedestrians waiting at the curb must judge the traffic moving in a circular motion, and they must deal with a significant amount of background traffic (i.e., noise) present at the main intersection. The findings show that crossings at all CTL crossing locations are significantly more difficult for blind pedestrians than for sighted pedestrians. Blind pedestrians tend to face a greater risk and a greater amount of delay. Furthermore, the research shows that conflicting traffic flow in the turn lane has a significant effect on crossing performance for both pedestrian groups; however, the effect of noise-generating background traffic on blind pedestrian crossings is not significant. The study also concludes that for this experiment the location of the crosswalk (in the center of the turn lane or at the downstream end) does not have a significant effect on crossing judgment performance.

Decreased Responsiveness of Mature Dendritic Cells from Cord Blood to Chemotaxis Induced by CXCR4 Ligand CXCL12, and CCR7 Ligand CCL19 May Explain Lowered GVHD Associated with Cord Blood Tranplantation.

Cord blood has been successfully used as a transplantable source of hemopoietic stem cells with a relatively low incidence of graft-versus-host disease (GVHD). Mature dendritic cells (DC), as the most efficient antigen presenting cells, play a critical role in the pathogenesis of GVHD and their function is intimately linked to their capacity to migrate. Chemokines and their G-protein linked receptors are of particular importance in DC migration. CCR7 and CXCR4 are two chemokine receptors expressed on mature DC. Binding of CCR7 ligand, MIP-3β/CCL19 and CXCR4 ligand, SDF-1/CXCL12 induce chemotaxis of mature DC and are pivotal for DC to initiate their functions in vivo. We hypothesized that the relatively lowered level of GVHD elicited by cord blood, compared to adult cells, might be due, at least in part, to a reduced capability of cord blood DC to migrate to lymphoid organs to initiate immune reactions and to organs such as liver and skin where GVHD pathogenesis usually occurs. To begin testing this hypothesis, we randomly picked 16 cord blood donors and 14 adult blood donors and did paired comparison study on chemotactic responses of cord blood and adult blood DC to CXCL12 and CCL19. Monocytes were isolated from both cord blood and adult blood and cultured with GM-CSF and IL-4 for 5 days to generate immature DC. LPS was added into cell culture for an additional 1 day to induce the maturation of these DC. Mature DC were harvested on day 6. We found that cord blood DC expressed significantly reduced surface levels of CCR7 compared with that of adult blood DC (p = .00067) and migrated at significantly lower efficiency towards the CCR7 ligand, CCL19 than did adult blood DC (p=0.029). Cord blood DC expressed significantly higher surface expression of CXCR4 than adult blood DC (p = .0018), but migrated at significantly lower efficiency towards CXCR4 ligand, CXCL12 than adult blood DC (p=0.00012). The lowered responsiveness of mature cord blood DC to chemotaxis by CXCL12 may reflect the enhanced truncation of CXCR4 we found on these cells. Also, cord blood DC migrated less well than adult blood DC toward the combination of CXCL12 and CCL19 than adult blood DC (p = .0014). These results suggest that low incidence and pathogenesis of GVHD observed in cord blood might be due, at least in part, to reduced capability of cord blood mature DC to migrate to critical organs where immune reaction and inflammation occur, effects reflecting lowered expression of CCR7 and enhanced truncation of CXCR4 on mature cord blood DC.

Tacrolimus ointment 0.1% in the treatment of nickel-induced allergic contact dermatitis

Background Tacrolimus is a macrolactam that prevents the transcription of messenger RNA for various inflammatory cytokines in both helper T cells (types 1 and 2) (T H1 and T H2). It is currently approved for the treatment of moderate to severe atopic dermatitis, a Th2-mediated disease, in children and adults. Objective We sought to evaluate the safety and efficacy of tacrolimus ointment 0.1% in the treatment of nickel-induced allergic contact dermatitis, a T H1-mediated disease. Methods This was a double-blind, randomized, vehicle-controlled, bilateral paired comparison study to assess the safety and efficacy of topical tacrolimus (Protopic, Fujisawa Healthcare Inc, Deerfield, Ill) ointment 0.1% in the treatment of allergic contact dermatitis induced by nickel sulfate. Volunteers were individuals with known hypersensitivity to nickel. Reactivity to nickel was graded both as the investigator's global assessment and total signs and symptoms, which consisted of the cumulative grade from 0 to 4 for each of the following parameters: erythema, induration, vesiculation, and pruritus (range of scores: 0-16). Reactivity was assessed in the per-protocol group at 1 and 2 weeks after beginning treatment with study drug and control. Adverse events were assessed in the intent-to-treat population. Results Of the 19 volunteers who completed the study (per protocol), 18 had an improvement in total signs and symptoms with tacrolimus versus 10 patients with the vehicle. Of patients, 80% had an improvement in the investigator's global assessment score on the tacrolimus-treated site versus 30% of patients on the placebo-treated site. Overall, tacrolimus was more effective than placebo in ameliorating the nickel reaction. Although the tacrolimus treated site was clear or almost clear in a greater number of individuals at week 1, this difference did not become significant until the second week of the study. Other than application site burning in 25% of volunteers, no significant adverse events were noted in the intent-to-treat population. Conclusion Topical tacrolimus (Protopic, Fujisawa Healthcare Inc) ointment 0.1% may be an option for the treatment of allergic contact dermatitis induced by nickel.

How Do Euro NCAP Results Correlate with Real-Life Injury Risks? A Paired Comparison Study of Car-to-Car Crashes

The European New Car Assessment Program (Euro NCAP) is a resource for consumers regarding vehicle crash safety. The program promotes safety developments, and credits car manufacturers for focusing on safety. This study was based on real-life car-to-car crashes and results show that the overall indication of the safety level, provided by the Euro NCAP crash testing, is a valid prediction when considering severe or fatal injuries. No significant injury risk differences were seen for minor injury crashes. In car-to-car collisions, cars with three or four stars were found to be approximately 30% safer when compared with two-star cars or cars without a Euro NCAP score. The strong correlation between injury risk and Euro NCAP scores is not necessarily similarly good for individual car models. Pedestrian safety and child occupant protection were not considered in the present study.

Imiquimod cream in the treatment of actinic keratoses

We studied the usefulness of imiquimod cream in the treatment of 3 patients with actinic keratoses. One patient was treated 3 times per week for 4 weeks and had a marked inflammatory response with nearly complete resolution of actinic keratoses. Two subsequent patients were treated in a bilateral paired comparison study. Both patients had similar numbers of actinic keratoses on symmetric areas and treated only one side with imiquimod cream 2 to 3 times per week with frequent rest periods to avoid inflammation. Both experienced marked reductions in actinic keratoses. After 8 weeks, both patients applied imiquimod cream twice per week for 9 months with continued reduction in actinic keratoses on both sides. Treatments were well tolerated. Imiquimod cream appears to be effective in the treatment of actinic keratoses. The main adverse effect is local inflammation, which can be avoided by reducing the frequency of application. (J Am Acad Dermatol 2002;47:S236-9.)

Stimulus set effects in the similarity ratings of unfamiliar complex sounds.

This study examined the effect of the distribution of values for various acoustic properties on the similarity ratings obtained in a paired-comparison study of complex sounds. Listeners rated the similarity of tones and tone complexes in one of four sets. Across the four sets both component frequency and the number of components in the stimuli were drawn from distributions that were either categorical or noncategorical. Other acoustic properties were distributed similarly in all sets. Solutions suggested that frequency was most important to the ratings, followed by the number of components in each critical band. Results suggest that when the values of an acoustic property are distributed categorically, its importance to similarity ratings increases relative to that observed with a less categorical distribution.

Modelling dependencies in paired comparison data: A log-linear approach

In many Bradley–Terry models a more or less explicit assumption is that all decisions of the judges are independent. An assumption which might be questionable at least for the decisions of a given judge. In paired comparison studies, a judge chooses among objects several times, and in such cases, judgements made by the same judge are likely to be dependent. A log-linear representation for the Bradley–Terry model will be developed, which takes into account dependencies between judgements. The modelling of the dependencies is embedded in the analysis of multiple binomial responses, which has the advantage of interpretability in terms of conditional odds ratios. Furthermore, the modelling is done in the framework of generalized linear models, thus parameter estimation and the assessment of goodness of fit can be obtained in the standard way by using e.g. GLIM or another standard software.

Relative rates of growth of annoyance of impulsive and non-impulsive noises.

Twenty-nine people judged the relative annoyance of five variable level signals and 29 impulsive and non-impulsive fixed-level signals in an adaptive paired comparison study. Signals were presented for judgment as heard indoors in a facility capable of accurately reproducing the very low-frequency content of sonic booms. When the annoyance of sonic booms unaccompanied by rattle was compared with that of sounds containing more higher-frequency energy (an aircraft flyover and an octave band of noise centered at 1 kHz), the relative rate of growth of annoyance, as expressed in C-weighted SEL units, was nearly 2:1. In other words, to maintain subjective equality of annoyance, each increase in level of sonic booms had to be matched by nearly twice the increase in level of an aircraft flyover or an octave band of noise centered at 1 kHz. Relative rates of growth of annoyance of sonic booms accompanied by rattle and of non-impulsive sounds, including both low- (63-Hz octave band of noise) and high-frequency energy (1-kHz octave band of noise and an aircraft flyover), were closer to 1:1. Relative rates of growth of annoyance for sonic booms unaccompanied by rattle and low-frequency sounds (63 Hz) were also about 1:1. These differences in relative rates of growth of annoyance of impulsive and non-impulsive sounds are as plausibly attributed to their relative low-frequency content as to impulsiveness per se. It may therefore be more useful for some purposes to express the annoyance of impulsive signals and other environmental noises containing substantial low-frequency energy in terms of effective (duration-corrected) loudness level rather than commonplace ASEL or CSEL.

Individual differences in paired comparison data.

Thurstonian models provide a flexible framework for the analysis of multiple paired comparison judgments because they allow a wide range of hypotheses about the judgments' mean and covariance structures to be tested. However, applications have been limited to a large extent by the computational intractability involved in fitting this class of models. This paper demonstrates that the Monte Carlo EM algorithm facilitates maximum likelihood estimation of Thurstonian paired comparison models even when the number of items is large. A paired comparison study is presented in detail to illustrate the estimation approach.