Oviposition behaviour and host colony size discrimination in Episyrphus balteatus (Diptera: Syrphidae).

Three bioassays were used to examine the oviposition behaviour of the hoverfly, Episyrphus balteatus (Degeer) in which various stimuli purported to influence host assessment and choice were tested. Episyrphus balteatus failed to exhibit enhanced behavioural responses, in terms of approaches and landings, to artificial leaves with the highest numbers of aphids, suggesting that females are merely responding to the colour of the artificial leaves. A density-dependent oviposition response was reported in a second bioassay using whole bean plants, although there was an asymptotic relationship. Syrphid responses, which were measured by oviposition over a five-day period, were greatest towards those plants with the highest number of aphids. In a final series of trials, gravid female E. balteatus showed a behavioural preference for filter papers treated with the greatest honeydew concentrations (0.26 mg microl(-1) honeydew). More time was spent in the treated areas and syrphids demonstrated more proboscis and ovipositor extensions in these treatments. These bioassays provided an opportunity to isolate some of the individual components of decision-making by female E. balteatus during egg-laying behaviour. A greater understanding of natural enemy behaviour is essential before enhanced control of pest populations in the field can be established.

The relationship of lumbar flexion to disability in patients with low back pain.

BACKGROUND AND PURPOSE: Physical therapists routinely assess spinal active range of motion (AROM) in patients with low back pain (LBP). The purpose of this study was to use 2 approaches to examine the relationship between impairment of lumbar spine flexion AROM and disability. One approach relied on the use of normative data to determine when an impairment in flexion AROM was present. The other approach required therapists to make judgments of whether the flexion AROM impairment was relevant to the patient's disability. SUBJECTS: Fifteen physical therapists and 81 patients with LBP completed in the study. METHODS: Patients completed the Roland-Morris Back Pain Questionnaire (RMQ), and the therapists assessed lumbar spine flexion AROM using a dual-inclinometer technique at the initial visit and again at discharge. RESULTS: Correlations between the lumbar flexion AROM measure and disability were low and did not vary appreciably for the 2 approaches tested. CONCLUSION AND DISCUSSION: Measures of lumbar flexion AROM should not be used as surrogate measures of disability. Lumbar spine flexion AROM and disability are weakly correlated, suggesting that flexion AROM measures should not be used as treatment goals.

Treatment categories for low back pain: a methodological approach.

Studies that evaluate effectiveness of physical therapy can be problematic because frequently several treatment techniques are used during an episode of care. Methods that categorize treatment techniques into discrete categories may be useful in studying treatment outcomes. The purpose of this study was to describe a method to create treatment categories used for patients with low back pain. We surveyed physical therapists in Virginia to identify frequently used treatments for patients with low back pain. One hundred fifty-five surveys were completed. Twenty-eight treatments, used frequently or very frequently by 50% or more of the respondents, were retained for analysis. Factor analysis was used to identify treatment categories. Seven categories were identified: McKenzie approach, manual therapy, exercise with equipment, active and stretching exercise, physical agents, aerobic exercise and walking, and ergonomic activities. Indices for the categories were created. Confirmatory factor analyses should be performed on a different sample to validate these findings.

Intertester reliability of a modified version of McKenzie's lateral shift assessments obtained on patients with low back pain.

BACKGROUND AND PURPOSE: McKenzie described a two-step process for assessing patients with low back pain for a lateral shift. The purpose of this study was to determine whether reliable judgments about lateral shifts could be obtained. SUBJECTS: Forty-nine patients with low back pain were each examined separately by two randomly paired physical therapists. METHODS: Assessments of the presence and direction of lateral shifts (step 1) were obtained by use of a simple instrument. The relevance of the lateral shifts to the patients' pain complaints (step 1) also was assessed by use of the side-glide test sequence. RESULTS: Generalized kappa coefficients were calculated to determine reliability. The kappa value for the two-step process of lateral shift assessment was .16. The percentage of agreement was 47%. CONCLUSION AND DISCUSSION: Each step in this two-step process was examined separately for possible sources of error. The kappa value for determinations of the presence and direction of lateral shifts was .00, indicating very poor reliability. The kappa value for the determination of the presence of a positive side-glide test sequence was .74, indicating high reliability. The role of lateral shift assessment in the McKenzie system should be reconsidered, given the strong research evidence for poor reliability of determinations of the presence and direction of lateral shifts.

The effect of lumbar support belts on isometric force production during a simulated lift.

The use of back support belts by industrial workers has become common in recent years. The rationale for the use of these belts is based on the theory that they increase intra-abdominal pressure. Raised intra-abdominal pressure is believed to reduce compression forces on the spinal column and to assist the back extensor muscles in producing extension torque. The assistance of the belt is believed to protect the spine from injury. Thirty males and thirty females participated in this study which assessed the effect of two different back support belts (one synthetic and one leather) on isometric muscle-force production of individuals performing a static leg lift (SLL). A Latin Square double cross-over design was employed. Analysis of variance tests revealed that in males the use of the synthetic belt allowed for greater force production than a control trial, but no difference could be detected between the leather belt and either the synthetic belt or the control. In the female group, no difference in force production occurred across the three conditions. Implications and suggestions for further study are discussed.

The influence of age and gender on lumbar spine sagittal plane range of motion. A study of 1126 healthy subjects.

Inclinometers have been recommended for the measurement of lumbar spine range of motion (ROM) in the assessment of disability. Range of motion thresholds that determine impairment ratings have been established without regard to age and gender or variances of the measures. This investigation determined the effect of gender and age on lumbar spine sagittal plane ROM in 1126 healthy male and female volunteers. Results indicate that distinct differences exist between men and women in flexion angle and extension angle, whereas little difference exists between genders for total lumbar sagittal ROM. Total sagittal ROM, flexion angle, and extension angle declined as age increased. Because of the high degree of variability in the measurements, detecting impairment in ROM with this method is problematic.

Reliability of measurements obtained by use of an instrument designed to indirectly measure iliotibial band length.

Ober's test is widely used to indirectly assess iliotibial band length on patients with painful conditions of the lower extremity. The validity of Ober's test is questioned on several accounts: there is no method for standardizing the position of the pelvis during the measurement; the scale used to describe the results is nominal and appears to have been arbitrarily determined; and, finally, the reliability of judgments made using Ober's test has not been reported. The purposes of this study were to develop a method for quantifying an indirect measurement of iliotibial band length and to examine the intratester and intertester reliability of measurements obtained. Iliotibial band lengths of 10 patients (N = 10) with anterior knee pain were measured twice by each of two examiners. Data were analyzed using the intraclass correlation coefficient (ICC) and standard error of the measurement (SEM). The ICC values were 0.94 and 0.73 for intratester and intertester reliability, respectively. The SEM values were 1 degree and 2 degrees for intratester and intertester reliability, respectively. Measurements obtained with the modified method are reliable when taken on young patients with anterior knee pain.

Back support mechanisms during manual lifting.

The ability of individuals to lift heavy loads without injury to the vertebral elements has led to the formulation of several explanations of this phenomenon. In this article, the existing literature on lifting is reviewed and mechanisms of back support during lifting are described. These mechanisms include the intra-abdominal pressure mechanism, the thoracolumbar fascia mechanism, and combinations of these mechanisms with the use of the erector spinae, multifidus, and psoas muscles. Physical therapists are often responsible for teaching patients and workers "proper" lifting techniques; however, controversy exists concerning the proper lift. Although lifting with the lower back in flexion and lifting in extension have been proposed, there are indications for each depending on individual circumstances. Lifting instructions for workers without low back injuries should be distinguished from instructions for patients with low back pain. General rules for lifting include: plan the lift, avoid twisting, keep the load close to the body, and bend at the knees.

High-power narrow-linewidth Er(3+)-doped fiber laser.

We describe a high-power Er(3+) laser that produces 56 +/- 2 and 96 +/- 5 mW of power at room and liquid-nitrogen temperatures, respectively. Slope efficiencies of 10 +/- 1% and 14 +/- 1% with corresponding thresholds of 44 +/- 4 and 6.8 +/- 0.6 mW are obtained at high and low temperatures. An intracavity étalon composed of the output mirror and the fiber end face restricted the output linewidth to 620 +/- 60 MHz.

Determination of the phase of the complex nonlinear refractive index by transient two-wave mixing in saturable absorbers.

The ratio of the imaginary part to the real part of the complex nonlinear refractive index has been measured by transient two-wave mixing in acridine-orange-doped fluorophosphate glass, fluorescein-doped boric-acid glass, and ruby at argon-ion wavelengths. The method enables the individual signs of the components of the nonlinear index to be obtained. A simple theory based on a single homogeneously broadened absorption from the ground state agrees with measurements of the phase of the nonlinear index in acridine but not in fluorescein, where our data suggest that excited-state absorption plays an important role.

Giant verrucous carcinoma in a giraffe.

An 18-year-old male giraffe developed a verrucous lesion, 50 cm in diameter, on a flank. Some areas of the lesion were histologically typical of a viral verruca with papillomatosis, prominent hypergranulosis, and inclusion bodies. The bulk of the mass was a well-differentiated verrucous type of squamous cell carcinoma. It may be that the virus of the verruca also caused the verrucous carcinoma.

Intensity ratios of (2)D(5/2,3/2)?(2)S doublets in the two-photon absorption spectrum of Rb and Cs.

Absorption ratios of doublets arising from n(2)D(5/2,3/2)? n'(2)S transitions in Rb (n = 5-9, n' = 5) and Cs (n = 7-13, n' = 6) were measured by Doppler-free two-photon spectroscopy using a thermionic ion detector. The observed ratios agree with calculated values for transitions to the higher levels but differ significantly for levels n = 5 in Rb and n =7, 8 in Cs. These experiments also provide new lower bounds for the ionization potentials of Rb(2) (3.62 eV) and Cs(2) (3.682 eV).