Measurement of the ^{13}C(α, n_{0})^{16}O Differential Cross Section from 0.8 to 6.5 MeV

The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.

The effects of head mounted weight on comfort for helmets and headsets, with a definition of "comfortable wear time"

BACKGROUND

There are difficult tradeoffs when designing head-mounted equipment such as helmets, lights, cameras, or virtual or augmented reality displays. Increased functionality and battery life adds weight, which in turn reduces comfort. A successful product must balance both comfort and functionality to achieve its product engagement goals.

OBJECTIVE

This study defines "comfortable wear time" as a new metric, and applies it to the domain of headsets in determining the relationship between headset weight and comfort.

METHODS

Sixteen study participants wore four otherwise identical headsets weighted between 500g-600 g for up to two hours each in an office environment. If participants experienced more than "mild discomfort" (>3 on an NRS-11 discomfort scale), the trial ended early, and the comfortable wear time was recorded. Intensity and location of discomfort was rated at trial conclusion, and qualitative feedback collected.

RESULTS

Higher weights were associated with shorter comfortable wear times. Not everyone could wear even the lightest headset (500 g) for the full two hours. Qualitatively, discomfort took many forms beyond the expected neck fatigue or contact pressure and included symptoms commonly associated with motion sickness, such as headache and dizziness. Finally, there were pronounced gender differences with females experiencing more severe discomfort with earlier onset.

CONCLUSION

Heavier headsets were less comfortable for the lower quartile of participants -yielding an average of 11 fewer minutes of comfortable wear time per 33 g of weight added. Understanding the discomfort costs from adding weight empowers product teams to find the correct balance to meet their product engagement targets.

Clinical validation of an adapted Eleveld Model for high-dose propofol treatments for depression

Repeated administration of high doses of propofol to patients with treatment-resistant depression (TRD) has been shown to produce antidepressant effects in small clinical trials. These effects can be elicited when the patient's EEG burst-suppression ratio (BSR) is maintained at 70-90% for 15 min in repeated treatments. This deep anesthesia domain lies beyond the range of current propofol pharmacokinetic/pharmacodynamic (PK/PD) models. In this study, we adapt the Eleveld model for use at deep anesthesia levels with a BSR endpoint, with the goal of aiding the estimation of the dosage of propofol needed to achieve 70-90% BSR for 15 min. We test the ability of the adapted model to predict BSR for these treatments. Twenty participants underwent 6-9 treatments of high doses of propofol (5-9 of which were included in this analysis) for a total of 115 treatments. To adapt the Eleveld model for this endpoint, we optimized the model parameters Ke0, γ and Ce50. These parameters were then used in the adapted model to estimate second-by-second BSR for each treatment. Estimated BSR was compared with observed BSR for each treatment of each participant. Median absolute performance error (MdAPE) between the estimated and observed BSR (25th-75th percentile) was 6.63 (3.79-12.96) % points and 8.51 (4.32-16.74) % between the estimated and observed treatment duration. This predictive performance is statistically significantly better at predicting BSR compared with the standard Eleveld model at deep anesthesia levels. Our adapted Eleveld model provides a useful tool to aid dosing propofol for high-dose anesthetic treatments for depression.

Evaluation of flat, angled, and vertical computer mice and their effects on wrist posture, pointing performance, and preference

BACKGROUND

Modern computer users use the mouse almost three times as much as the keyboard. As exposure rates are high, improving upper extremity posture while using a computer mouse is desirable due to the fact that posture is one risk factor for injury. Previous studies have found posture benefits associated with using alternative mouse designs, but at the cost of performance and preference.

OBJECTIVE

To develop new computer mouse shapes, evaluate them versus benchmarks, and determine whether there are differences in wrist posture, pointing performance, and subjective measures.

METHODS

Three concept mice were designed and evaluated relative to two existing benchmark models: a traditional flat mouse, and an alternative upright mouse. Using a repeated measures design, twelve subjects performed a standardized point-and-click task with each mouse. Pointing performance and wrist posture was measured, along with perceived fatigue ratings and subjective preferences pre and post use.

RESULTS

All of the concept mice were shown to reduce forearm pronation relative to the traditional flat mouse. There were no differences in pointing performance between the traditional flat mouse and the concept mice. In contrast, the fully vertical mouse reduced pronation but had the poorest pointing performance. Perceived fatigue and subjective preferences were consistently better for one concept mouse.

CONCLUSIONS

Increasing mouse height and angling the mouse topcase can improve wrist posture without negatively affecting performance.

Holding a tablet computer with one hand: effect of tablet design features on biomechanics and subjective usability among users with small hands

The purpose of this study was to evaluate tablet size (weight), orientation, grip shape, texture and stylus shape on productivity, biomechanics and subjective usability and fatigue when the tablet was held with just the left hand. A total of 15 male and 15 female subjects, ages 16-64 years, tested eight tablets and three styluses. Overall, the usability, fatigue and biomechanical evaluation of tablet design features supported the use of smaller to medium-sized tablets, with a ledge or handle shape on the back and surfaced with a rubberised texture. Larger, heavier tablets had significantly worse usability and biomechanics and their use with one hand should be limited. The stylus with a tapered grip (7.5-9.5 mm) or larger grip (7.6 mm) had better usability and biomechanics than one with a smaller grip (5 mm). There were no significant differences in productivity between design features. These design parameters may be important when designing tablets.

PRACTITIONER SUMMARY

Different tablet and stylus design features were evaluated for usability and biomechanical properties. On the basis of short-term tasks, emulating functional tablets, usability was improved with the smaller and medium-sized tablets, portrait (vs. landscape) orientation, a back ledge grip and rubberised texture. There were no differences in productivity between design features.

The effect of keyboard key spacing on typing speed, error, usability, and biomechanics: Part 1

OBJECTIVE

In this study, we evaluated the effects of key spacing on a conventional computer keyboard on typing speed, percentage error, usability, and forearm muscle activity and wrist posture.

BACKGROUND

International standards that specify the spacing between keys on a keyboard have been guided primarily by design convention because few studies have evaluated the effects of key spacing on productivity, usability, and biomechanical factors.

METHOD

Experienced male typists (N = 37) with large fingers (middle finger length > or = 8.7 cm or finger breadth of > or = 2.3 cm) typed on five keyboards that differed only in horizontal and vertical key spacing (19 x 19 mm, 18 x 19 mm, 17 x 19 mm, 16 x 19 mm, and 17 x 17 mm) while typing speed, percentage error, fatigue, preference, extensor carpi ulnaris and flexor carpi ulnaris muscle activity, and wrist extension and ulnar deviation were recorded.

RESULTS

Productivity and usability ratings were significantly worse for the keyboard with spacing of 16 x 19 mm compared with the other keyboards. Differences on these measures between the other keyboards were not significant. Muscle activity tended to increase in the left forearm and decrease in the right with decreasing horizontal key spacing. There was also a trend for left wrist extension to increase and left ulnar deviation to decrease with decreasing horizontal key spacing. Reducing vertical key spacing from 19 to 17 mm had no significant effect on productivity or usability ratings.

CONCLUSIONS

The study findings support key spacing on a computer keyboard between 17 and 19 mm in both vertical and horizontal directions.

APPLICATIONS

These findings may influence keyboard standards and the design of keyboards.

Enabling comfortable thumb interaction in tablet computers: a Windows 8 case study

Holding a tablet computer in two hands and interacting via the thumbs is an important and commonly observed method of tablet interaction. This paper presents a methodology for measuring and reporting thumb reach in a way that enables designers of user interfaces (UI) to design UIs that can be comfortably reached by the thumbs. The process is to identify the relevant anthropometric measure and target population, identify how people grip the device, measure reach areas for different groups and grips, and to use the data to create graphical ‘heat maps’ along with guidance that designers can use to place their interface elements into easily reachable areas of the screen. The methodology is illustrated with an example of how it was used in the development of Microsoft Windows 8.

Touch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles

OBJECTIVE

The aim of this study was to determine how head and neck postures vary when using two media tablet (slate) computers in four common user configurations.

METHODS

Fifteen experienced media tablet users completed a set of simulated tasks with two media tablets in four typical user configurations. The four configurations were: on the lap and held with the user's hands, on the lap and in a case, on a table and in a case, and on a table and in a case set at a high angle for watching movies. An infra-red LED marker based motion analysis system measured head/neck postures.

RESULTS

Head and neck flexion significantly varied across the four configurations and across the two tablets tested. Head and neck flexion angles during tablet use were greater, in general, than angles previously reported for desktop and notebook computing. Postural differences between tablets were driven by case designs, which provided significantly different tilt angles, while postural differences between configurations were driven by gaze and viewing angles.

CONCLUSION

Head and neck posture during tablet computing can be improved by placing the tablet higher to avoid low gaze angles (i.e. on a table rather than on the lap) and through the use of a case that provides optimal viewing angles.

Changes in posture through the use of simple inclines with notebook computers placed on a standard desk

This study evaluated the use of simple inclines as a portable peripheral for improving head and neck postures during notebook computer use on tables in portable environments such as hotel rooms, cafés, and airport lounges. A 3D motion analysis system measured head, neck and right upper extremity postures of 15 participants as they completed a 10 min computer task in six different configurations, all on a fixed height desk: no-incline, 12° incline, 25° incline, no-incline with external mouse, 25° incline with an external mouse, and a commercially available riser with external mouse and keyboard. After completion of the task, subjects rated the configuration for comfort and ease of use and indicated perceived discomfort in several body segments. Compared to the no-incline configuration, use of the 12° incline reduced forward head tilt and neck flexion while increasing wrist extension. The 25° incline further reduced head tilt and neck flexion while further increasing wrist extension. The 25° incline received the lowest comfort and ease of use ratings and the highest perceived discomfort score. For portable, temporary computing environments where internal input devices are used, users may find improved head and neck postures with acceptable wrist extension postures with the utilization of a 12° incline.

Effects of keyboard keyswitch design: a review of the current literature

OBJECTIVE

This article aims to provide designers and researchers with a summary of the current literature regarding the effects of specific keyswitch design parameters on user preference, performance, and biomechanical outcomes.

METHODS

Studies which evaluated the effects of keyswitch make force, make travel and over travel on preference, typing speed, errors, keyboard reaction forces and upper extremity EMG are included in the review. Studies which examined possible control strategies employed during keyswitch tapping are also covered.

RESULTS

General conclusions that can be drawn from these studies are: greater make forces result in increased keyboard reaction forces and EMG activity, users strike keys with forces 2-7 times the required make force and that they employ a ballistic finger motion to do so. Furthermore, typists tend to prefer kinesthetic and auditory feedback.

CONCLUSIONS

Due to the ballistic nature of typing, new keyswitch designs should be aimed at reducing impact forces. Future studies should examine the role of breakaway force and over travel as limited research has been done on the role of these parameters.

Notebook computer use on a desk, lap and lap support: effects on posture, performance and comfort

This study quantified postures of users working on a notebook computer situated in their lap and tested the effect of using a device designed to increase the height of the notebook when placed on the lap. A motion analysis system measured head, neck and upper extremity postures of 15 adults as they worked on a notebook computer placed on a desk (DESK), the lap (LAP) and a commercially available lapdesk (LAPDESK). Compared with the DESK, the LAP increased downwards head tilt 6 degrees and wrist extension 8 degrees . Shoulder flexion and ulnar deviation decreased 13 degrees and 9 degrees , respectively. Compared with the LAP, the LAPDESK decreased downwards head tilt 4 degrees , neck flexion 2 degrees , and wrist extension 9 degrees. Users reported less discomfort and difficulty in the DESK configuration. Use of the lapdesk improved postures compared with the lap; however, all configurations resulted in high values of wrist extension, wrist deviation and downwards head tilt. STATEMENT OF RELEVANCE: This study quantifies postures of users working with a notebook computer in typical portable configurations. A better understanding of the postures assumed during notebook computer use can improve usage guidelines to reduce the risk of musculoskeletal injuries.

Children and computer use in the home: workstations, behaviors and parental attitudes

This study examines the home computer use of 26 children (aged 6-18) in ten upper middle class families using direct observation, typing tests, questionnaires and semi-structured interviews. The goals of the study were to gather information on how children use computers in the home and to understand how both parents and children perceive this computer use. Large variations were seen in computing skills, behaviors, and opinions, as well as equipment and workstation setups. Typing speed averaged over 40 words per minute for children over 13 years old, and less than 10 words per minute for children younger than 10. The results show that for this sample, Repetitive Stress Injury (RSI) concerns ranked very low among parents, whereas security and privacy concerns ranked much higher. Meanwhile, children's behaviors and workstations were observed to place children in awkward working postures. Photos showing common postures are presented. The greatest opportunity to improve children's work postures appears to be in providing properly-sized work surfaces and chairs, as well as education. Possible explanations for the difference between parental perception of computing risks and the physical reality of children's observed ergonomics are discussed and ideas for further research are proposed.

Providing training enhances the biomechanical improvements of an alternative computer mouse design

OBJECTIVE

The purpose of this study is to determine if an alternative mouse promotes more neutral postures and decreases forearm muscle activity and if training enhances these biomechanical benefits.

BACKGROUND

Computer mouse use is a risk factor for developing musculoskeletal disorders; alternative mouse designs can help lower these risks. Ergonomic training combined with alternative input devices could be even more effective than alternative designs alone.

METHODS

Thirty healthy adults (15 males, 15 females) performed a set of computer mouse tasks with a standard mouse and an alternative mouse while an electromagnetic motion analysis system measured their wrist and forearm postures and surface electromyography measured the muscle activity of three wrist extensor muscles. Fifteen participants received no training on how to hold the alternative mouse, whereas the remaining 15 participants received verbal instructions before and during use of the alternative mouse.

RESULTS

The alternative mouse was found to promote a more neutral forearm posture compared with the standard mouse (up to 11.5 degrees lower forearm pronation); however, pronation was further reduced when instructions on how to hold the mouse were provided. Wrist extensor muscle activity was reduced for the alternative mouse (up to 1.8% of maximum voluntary contraction lower) compared with the standard mouse, but only after participants received instructions.

CONCLUSION

The alternative mouse design decreased biomechanical exposures; however, instructions enhanced this potential ergonomic benefit of the design.

APPLICATION

User knowledge and training are important factors when effectively implementing an alternative ergonomic device.

The effects of split keyboard geometry on upper body postures

Split, gabled keyboard designs can prevent or improve upper extremity pain among computer users; the mechanism appears to involve the reduction of awkward wrist and forearm postures. This study evaluated the effects of changes in opening angle, slope and height (independent variables) of a gabled (14 degrees) keyboard on typing performance and upper extremity postures. Twenty-four experienced touch typists typed on seven keyboard conditions while typing speed and right and left wrist extension, ulnar deviation, forearm pronation and elbow position were measured using a motion tracking system. The lower keyboard height led to a lower elbow height (i.e. less shoulder elevation) and less wrist ulnar deviation and forearm pronation. Keyboard slope and opening angle had mixed effects on wrist extension and ulnar deviation, forearm pronation and elbow height and separation. The findings suggest that in order to optimise wrist, forearm and upper arm postures on a split, gabled keyboard, the keyboard should be set to the lowest height of the two heights tested. Keyboard slopes in the mid-range of those tested, 0 degrees to -4 degrees, provided the least wrist extension, forearm pronation and the lowest elbow height. A keyboard opening angle in the mid-range of those tested, 15 degrees, may provide the best balance between reducing ulnar deviation while not increasing forearm pronation or elbow separation. These findings may be useful in the design of computer workstations and split keyboards. The geometry of a split keyboard can influence wrist and forearm postures. The findings of this study are relevant to the positioning and adjustment of split keyboards. The findings will also be useful for engineers who design split keyboards.

Smaller external notebook mice have different effects on posture and muscle activity

BACKGROUND

Extensive computer mouse use is an identified risk factor for computer work-related musculoskeletal disorders; however, notebook computer mouse designs of varying sizes have not been formally evaluated but may affect biomechanical risk factors.

METHODS

Thirty adults performed a set of mouse tasks with five notebook mice, ranging in length from 75 to 105 mm and in width from 35 to 65 mm, and a reference desktop mouse. An electro-magnetic motion analysis system measured index finger (metacarpophalangeal joint), wrist and forearm postures, and surface electromyography measured muscle activity of three extensor muscles in the forearm and the first dorsal interosseus.

FINDINGS

The smallest notebook mice were found to promote less neutral postures (up to 3.2 degrees higher metacarpophalangeal joint adduction; 6.5 degrees higher metacarpophalangeal joint flexion, 2.3 degrees higher wrist extension) and higher muscle activity (up to 4.1% of maximum voluntary contraction higher wrist extensor muscle activity). Participants with smaller hands had overall more non-neutral postures than participants with larger hands (up to 5.6 degrees higher wrist extension and 5.9 degrees higher pronation); while participants with larger hands were more influenced by the smallest notebook mice (up to 3.6 degrees higher wrist extension and 5.5% of maximum voluntary contraction higher wrist extensor values). Self-reported ratings showed that while participants preferred smaller mice for portability; larger mice scored higher on comfort and usability.

INTERPRETATION

The smallest notebook mice increased the intensity of biomechanical exposures. Longer term mouse use could enhance these differences, having a potential impact on the prevention of work-related musculoskeletal disorders.

Evaluation of a dynamic arm support for seated and standing tasks: a laboratory study of electromyography and subjective feedback

The goal of this study was to determine whether a new dynamic arm support system reduced shoulder and arm muscle load for seated and standing hand/ arm tasks. The new system provides support for both horizontal and vertical arm motion. A total of 11 participants performed ten tasks (five seated and five standing) both with and without the arm support. Outcomes were assessed with electromyography and subjective feedback. Muscle activity was measured over the dominant side supraspinatus, triceps and forearm extensor muscles. Significant (p < 0.01) reductions in static muscle activity were observed in one of ten tasks performed with the support device for the supraspinatus muscle, in five tasks for the triceps and in one task for forearm extensor muscles. Likewise, a significant improvement in subjective measures was reported with the support device for 'ease of task' for two of ten tasks, for 'forearm comfort' for three of ten tasks and for 'shoulder effort' for six of ten tasks. The results suggest that a dynamic forearm support may improve subjective comfort and reduce static muscle loads in the upper extremity for tasks that involve horizontal movement of the arms. For rapid motions, the value of the support is limited due to internal inertia and friction.

The association of MHC genes with autism

Several immune abnormalities have been noted in autistic subjects. These associations have been extended to the Major Histocompatibility Complex (MHC), a section of DNA remarkable for the number of encoded proteins with immunological functions. The strongest MHC association identified thus far is for the null allele of C4B in the class III region. The complex allelic composition of C4 as determined by immunoelectrophoresis is discussed. Low levels of C4 resulting from the null allele may be important in disease pathogenesis especially since C4 has been identified in developing brain neurons. The DNA region just telomeric to C4 has several genes including tumor necrosis factor which encode proteins with immunological functions. These proteins may act in concert with C4 in disease contribution and the genes should be more closely examined.

Phase I study of oral JM216 given twice daily

JM216 [bis-acetato-ammine-dichloro-cyclohexylamine-platinum(IV)] is an oral platinum complex that is currently in phase II trials in ovarian cancer and lung cancer on a daily-times-5 schedule. This trial examined an alternative schedule of two doses given 12 h apart, which may be better tolerated by patients. A total of 19 patients were given 50 cycles of treatment at doses ranging from 150 to 350 mg/m2 b.i.d. The study was stopped before the MTD was reached due to non-linear pharmacokinetics. Toxicity was similar to that encountered in previous phase I studies, with nausea, vomiting and diarrhoea being seen at all dose levels, although this was generally mild and short-lived, and grade 3 and 4 myelosuppression being seen at dose levels ranging from 250 to 350 mg/m2. There was no nephro-, oto-, or neurotoxicity, but one patient had an allergic reaction at 300 mg/m2 on the fifth and sixth cycles. No response was seen, but two patients with mesothelioma had stable disease and received six cycles. There was considerable interpatient variability in plasma pharmacokinetics at all dose levels. There was no relationship between dose and AUC (dose 1 and dose 2) or Cmax after dose 1. In a limited number of patients the first dose was given in the morning rather than in the evening, apparently resulting in lower AUC, Cmax and Tmax values at the 250-mg/m2 dose level, but this was not seen in one patient at 300 mg/m2. This study confirms that the pharmacokinetics of JM216 is non-linear and highly variable due to saturable absorption and that the daily times 5 schedule is the optimal schedule for further phase II trials.

Influence of membrane anchoring and cytoplasmic domains on the fusogenic activity of vesicular stomatitis virus glycoprotein G

Chimeric proteins in which the transmembrane anchoring sequence (TM) or both the TM and the cytoplasmic tail (CT) of vesicular stomatitis virus glycoprotein G were replaced with corresponding domains of viral or cellular integral membrane proteins were used to examine the influence of these domains on acidic-pH-induced membrane fusion by G protein. The TM and CT of G were also replaced with the lipid anchor glycosylphosphatidylinositol. Hybrids containing foreign TM or TM and CT sequences were fusogenic at acidic pH but glycosylphosphatidylinositol-anchored G was nonfusogenic at acidic pH. The results suggest that the fusogenic activity of G protein requires membrane anchoring by a hydrophobic peptide sequence and the specific amino acid sequence of the TM has no influence on fusogenic activity.

DR-positive T cells in autism: association with decreased plasma levels of the complement C4B protein

Autism is a developmental disorder characterized by severe communication, social and behavioral abnormalities. Over the past several years a fair amount of evidence has accumulated suggesting that some cases of autism may be associated with immune abnormalities and with products of the HLA complex including the C4B gene located in the class III region of HLA. This study sought additional evidence for an association of autoimmune processes with autism by investigating the presence of activated T cells in 26 autistic subjects. Fourteen of the autistic subjects had DR+ T cells, an indicator of activated T cells, but none of the autistic subjects had T cells expressing the interleukin-2 receptor, another indicator of T cell activation. Similar findings of incomplete or partial T cell activation have been reported in autoimmune disorders and in a recent study of autism. In the current investigation, the DR+ T cells were not found to be associated with age of the autistic patients but were inversely correlated with a decreased plasma level of the C4B protein. In conclusion, this study provides additional evidence for the involvement of an autoimmune mechanism in autism.

Decreased plasma concentrations of the C4B complement protein in autism

OBJECTIVE

To determine complement C4 protein concentrations in the plasmas of autistic subjects and their family members.

DESIGN

Cross-sectional study.

SETTING

Center for Persons with Disabilities and the Department of Biology, Utah State University, Logan.

PARTICIPANTS

Forty-two autistic subjects (34 males [81%] and eight females [19%]), 50 of their biologic parents, 21 siblings, and 105 normal subjects (56 females [53%] and 49 males [47%]; all white) living in northern Utah.

INTERVENTIONS

None.

METHODS

The enzyme-linked immunosorbent assay was used to determine C4 protein concentrations in autistic subjects.

MAIN RESULTS

Plasma concentration (median, 14.7 g/L of the C4B protein) in autistic patients was significantly (P = .01) decreased compared with that of normal subjects (median, 22.4 g/L). The C4B concentrations in parents and siblings of autistic children were decreased, but not significantly. The C4A protein concentrations in the plasma of autistic subjects and their family members were normal.

CONCLUSION

Decreased protein concentrations of C4B may be associated with autism.

Evidence of prenatal infection in the bottlenose dolphin (Tursiops truncatus) with the lungworm Halocercus lagenorhynchi (Nematoda: Pseudaliidae)

Adult lung nematodes identified as Halocercus lagenorhynchi were collected from the lungs of four Tursiops truncatus calves. The calves ranged in age from newborn to 3-wk-old and were found on both the Atlantic and Gulf coasts of Florida (USA). This finding suggests the possibility of a more cosmopolitan distribution of prenatal infection with lung nematodes in cetaceans than previously suspected.

Radioimmunoassay of serum follicle-stimulating hormone and luteinizing hormone in the bottlenosed dolphin

Commercially available radioimmunoassay (RIA) kits for human follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were adapted for quantitation of these hormones in serum from bottlenosed dolphins (Tursiops truncatus). Serum samples from over 160 wild and 70 captive animals were assayed in order to determine basal concentrations of FSH and LH in these animals, as well as to detect possible differences between various groups. Mean FSH and LH levels for all animals were 0.22 +/- 0.08 and 0.37 +/- 0.18 ng/ml, respectively. Although wild animals had higher FSH and LH levels than captive ones, the differences were not statistically significant (P less than 0.07). However, both FSH and LH were significantly (P less than 0.01 and P less than 0.05, respectively) elevated in females when compared to males. Adults and peripubescent animals had significantly (P less than 0.01) higher LH levels than did juveniles. Among wild animals, serum concentrations of FSH and LH reflected seasonal differences. Samples obtained in early summer (Gulf of Mexico population) contained significantly (P less than 0.01) higher concentrations of FSH and LH than samples obtained in the fall (Indian River, Florida population). Both FSH and LH were significantly elevated in samples from confirmed pregnant animals as compared to the overall mean and to a sample from a confirmed nonpregnant female. Our observations indicate that these RIAs can reliably detect serum FSH and LH from bottlenosed dolphins and represent the first quantitation of these hormones in cetaceans.