Two-stage robust control of substrate concentration for an activated sludge process.

A two-stage robust control scheme improving the performance of an Activated Sludge Process is proposed. In the first stage, asymptotic command following the substrate concentration with simultaneous attenuation of the fluctuations of the dissolved oxygen concentration is assured. The first stage is a pure dynamic controller. The second stage is a PID controller. Good performance of the proposed control scheme on the corresponding nonlinear ASP model is illustrated through extensive simulation experiments. The contribution of the paper can be summarized to the derivation of the following two results: An accurate to a wide range of inputs and disturbances, linearized generic model of the ASP and, most important, a linear robust controller that controls accurately the effluent substrate concentration without using measurements of it.

Clinical procedures for the neuropsychological evaluation of U.S. Air Force pilots.

The neuropsychological assessment of U.S. Air Force pilots presents several unique problems given their relatively high cognitive functioning. The U.S. Air Force currently has a baselining procedure whereby student pilots undergo computerized cognitive assessment. The intent of this assessment is to archive premorbid data against which to compare potential future postinsult performance. The current work provides the background, clinical methods, and data needed to assess pilots who have suffered cortical insult such as trauma, disease, or exposure to toxins. Methods are delineated for pilots with premorbid testing and for pilots without such testing.

Revised NEO Personality Inventory profiles of male and female U.S. Air Force pilots.

The study of pilot personality characteristics has a long and controversial history. Personality characteristics seem to be fairly poor predictors of training outcome; however, valid personality assessment is essential to clinical psychological evaluations. Therefore, the personality characteristics of pilots must be studied to ensure valid clinical assessment. This paper describes normative personality characteristics of U.S. Air Force pilots based on the Revised NEO Personality Inventory profiles of 1,301 U.S. Air Force student pilots. Compared with male adult norms, male student pilots had higher levels of extraversion and lower levels of agreeableness. Compared with female adult norms, female student pilots had higher levels of extraversion and openness and lower levels of agreeableness. Descriptive statistics and percentile tables for the five domain scores and 30 facet scores are provided for clinical use, and a case vignette is provided as an example of the clinical utility of these U.S. Air Force norms.

A comparison of two U.S. Air Force pilot aptitude tests.

BACKGROUND: The Air Force Officer Qualifying Test (AFOQT) and Multidimensional Aptitude Battery (MAB) were administered to 2233 U.S. Air Force pilot candidates to investigate the common sources of variance in those batteries. The AFOQT was operationally administered as part of the officer commissioning and aircrew selection testing requirement. The MAB is a clinical test battery and was administered to provide an intellectual baseline to assist clinicians when it becomes necessary to evaluate pilots with cognitive referral questions. RESULTS: A joint factor analysis of the AFOQT and MAB revealed that each battery had a hierarchical structure. The higher-order factor in the AFOQT previously had been identified as general cognitive ability (g). The intercorrelation between the higher-order factors from the batteries was 0.981, indicating that both measured g. Although both batteries measured g and included verbal, spatial, and perceptual speed tests, the AFOQT also included tests of aviation knowledge not found in the MAB. CONCLUSION: Additional studies are required to evaluate the utility of the AFOQT for clinical assessment and the MAB for officer and aircrew selection.

Interpersonal relationship and prisoner of war concerns of rated military male and female aircrew.

BACKGROUND: The issue of women flying military aircraft in a combat role has been very controversial. HYPOTHESIS: To succeed, female military aircrew are very similar to their male peers. METHODS: We conducted a comprehensive anonymous questionnaire survey of all U.S. Army and U.S. Air Force rated female aircrew, with an equal number of age and duty matched male aircrew. We are reporting on the interpersonal relationship and prisoner of war (P.O.W.) responses here. RESULTS: Male and female aircrew respond in a similar manner to posed questions, although differences do exist. Women reported: unequal treatment by opposite gender peers; problems relating to peers, superiors and subordinates; their gender influences assignments; the need to perform to higher standards and the need to work harder to be accepted as equals; ability to bond equally to their own and opposite gender peers; improved squadron cohesiveness in mixed gender squadrons; problems with peers' spouses; and, in a P.O.W. situation, fear of rape and sexual abuse. Men reported: women get inappropriate privileges and get special "breaks"; a gender difference in how flight duties are performed; worsened squadron cohesiveness in mixed gender squadrons; less likeliness to recommend their career path to their daughters; and a higher concern for welfare of families in a P.O.W. situation. CONCLUSIONS: Although responding in a similar manner to most questions, male and female military aircrew differ in the perception of their ability to function in mixed squadrons because of their gender. Some of these perceptions can be modified through training, others may need to be resolved through high level orders/policy; while in others, the military may have to accept women are different from men in some aspects.

Female United States Air Force pilot personality: the new right stuff.

With increasing numbers of female military pilots, it is important to understand the psychological and psychiatric gender differences of pilots. Using the "big five" personality structure (neuroticism, extraversion, openness to new experiences, agreeableness, and conscientiousness), female United States Air Force pilots were compared with both male Air Force pilots and to a female comparison group. Female Air Force pilots were higher on the Extraversion, Agreeableness, and Conscientiousness scales than male pilots. Female pilots were also higher on these scales than the female comparison group and lower on the Neuroticism and Openness scales than that comparison group. It is suggested that these traits are highly adaptive for Air Force pilots, given the nature of modern military operational requirements.

Women in combat: concerns of U.S. Air Force and U.S. Army rated male and female aircrew.

The issue of women flying military aircraft in a combat role has been very controversial. We conducted a comprehensive survey, via anonymous questionnaire, of all U.S. Army and U.S. Air Force rated female aircrew, with an equal number of age- and duty-matched male aircrew. Here we report on the women in combat section of the questionnaire: should women be allowed to fly aircraft on combat missions? if allowed to do so, should they have the option of doing so? The great majority of women (87%) felt that they should be allowed to fly aircraft on combat missions, whereas only 41% of the men agreed. If women were allowed to fly in combat, both genders felt that women should be forced to do so on an equal basis with the men. Major concerns were that there be no quotas, that combat slots be opened to the best qualified, and prisoner-of-war concerns. Many women opined that they should not be forced to go into combat because they believe men are not forced to do so. There seemed to be a great deal of animosity between men and women concerning women flying in combat.

Female United States Air Force (USAF) pilots: themes, challenges, and possible solutions.

BACKGROUND: Identification of stresses of mixed-gender squadrons, attention to the psychological concerns of pilots in combat, and recognition of the difficulties of balancing a career and family are important in today's United States Air Force (USAF). What qualities are desirable in male and female pilots in combat situations, how do men and women view their career and family goals, and how do men and women work together in day-to-day squadron activities versus deployment and combat situations? METHODS: A semi-structured clinical interview sought in formation about personal/family health, squadron relationships, and career/deployment stresses. The interview covered the effect of grounding for more than 30 d, motivation to fly, health decrements due to aircraft design, teamwork difficulties and blocks to success, career demands, combat and prisoner of war (POW) concerns, stress and coping styles, flying goals, and family/health concerns. There were 114 (64 male and 50 female) pilots who participated in the study. RESULTS: The majority of male pilots interviewed asserted that they would be more protective of a woman in combat than a man and were concerned about their reaction to a female POW. Many women were concerned about being used to exploit men in a POW camp. The majority of pilots believed women were well integrated into their squadrons. Those interviewed reported that the squadron members with the most difficulty dealing with women were older males, including enlisted crew and some commanders. CONCLUSION: The information gained from this study will assist the USAF in understanding and coping with the psychological stresses associated with combat, deployment, and mixed-gender squadrons.

Cognitive assessment of USAF pilot training candidates.

BACKGROUND: Most intellectual and cognitive assessment of pilots is done with locally developed assessment devices. The United States Air Force currently uses the recently developed CogScreen (Aeromedical Edition) to assess these areas. HYPOTHESES: There will be differences on the CogScreen across USAF student pilot candidates and commercial pilots. METHODS: This paper presents the test scores of 512 USAF pilot training candidates who were tested with this commercially available, "off-the-shelf" product. Comparison data was abstracted from the test manual on commercial pilots. RESULTS: Data from the new CogScreen (Aeromedical Edition) is provided and shows consistent differences between pilot training candidates and commercial pilots across reaction time, accuracy, throughput, and process measures. DISCUSSION: The new CogScreen appears to be an appropriate device for the assessment of pilot candidates, student pilots, and pilots.

Differential regulation of hippocampal AMPA and kainate receptor subunit expression by haloperidol and clozapine.

Dopamine-glutamate interactions within discrete neural circuits are increasingly recognized as potential substrates for dysregulation in schizophrenia, and as a result, potential targets for pharmacological intervention in this illness. We examined the regulation, by haloperidol (2 mg kg-1 day-1) and clozapine (20 mg kg-1 day-1), of the mRNAs encoding the four AMPA receptor subunits (gluR1-gluR4), three low-affinity kainate receptor subunits (gluR5-gluR7), and two high-affinity kainate subunits (KA1 and KA2) in the rat hippocampal formation and associated entorhinal cortex. A complex and differential pattern of AMPA and kainate subunit mRNA regulation by clozapine and haloperidol was observed in this study. Both drugs caused significant alterations of most of these mRNAs, but in a heterogeneous and region-specific fashion. These data suggest that these antipsychotic drugs alter the expression of the genes encoding the subunits that express ionotropic glutamate receptors. Given the importance of glutamatergic mechanisms and the hippocampal formation in schizophrenia, these data suggest a potential substrate for neurotransmitter dysregulation in this illness, as well as a potential target for therapeutic intervention.

Defining and measuring the "right stuff": neuropsychiatrically enhanced flight screening (N-EFS).

BACKGROUND: United States Air Force (USAF) commanders wish to make better pilot-selection and cockpit-assignment decisions. Also, some pilots will sustain head injuries that will affect their flying careers. The complex and unforgiving nature of aviation demands a conservative approach to occupational return after neurological insult. Therefore, a neuropsychological assessment is required to return to flying. The lack of pre-injury neuropsychological data, however, hinders accurate assessment of post-injury functioning. HYPOTHESES: a) Psychological data may improve the pilot selection and assignment processes as military resources dwindle; and b) baseline intellectual/cognitive data may support the scientific basis of aeromedical decision-making. METHODS: Neuropsychiatrically Enhanced Flight Screening (N-EFS) attempts to validate the Multidimensional Aptitude Battery (MAB), CogScreen, Revised NEO-PI (NEO-PI-R), and Personal Characteristics Inventory (PCI) for pilot selection and cockpit assignment. N-EFS also measures baseline intelligence (using the MAB) and cognitive functioning (using the CogScreen) for comparison purposes if a future medical flying waiver is needed after neurological insult. These assessments will compare the aviator's postinjury functioning to a personal intellectual functioning baseline captured at entry into aviation training. RESULTS: N-EFS students are scoring from below average to very superior in intellectual assessment. Very preliminary personality testing results suggest few significant differences between male and female student pilots, with high extraversion being the most striking personality characteristic. DISCUSSION: The wide range of intellectual functioning in pilot candidates argues for baseline data collection to improve future aeromedical decisions.

Assessing aviators for personality pathology with the Millon Clinical Multiaxial Inventory (MCMI).

Psychiatrists independently evaluated 82 aviators referred to an aeromedical consultation service who had been administered the Millon Clinical Multiaxial Inventory (MCMI). The MCMI personality scales of those aviators psychiatrically deemed to be free from personality pathology were compared to the scales of those aviators psychiatrically assessed to have maladaptive personalities. The MCMI personality scales reached statistical significance (p < 0.005) for identifying Diagnostic and Statistical Manual of Mental Disorders (2) Cluster C (dependent or avoidant or both) maladaptive personality traits, but did not reach statistical significance for Cluster B (histrionic or narcissistic or both) traits. Military aviators are a highly selected group who have mastered numerous obstacles and who continually prove their adaptability. The prevalence of personality pathology is likely not as great in this population as would be suggested by the MCMI. An elevation of a Cluster C scale, however, warrants a high index of suspicion.

Flight psychology at Sheppard Air Force Base.

Flight psychology is the application of psychological principles to the unique environment of the aviator in order to enhance training, flight safety, and mission accomplishment. At Sheppard Air Force Base, TX, flight psychology is a cooperative effort between a clinical psychologist and the aeromedical services, with the former acting as a consultant to the latter. The primary focus of the flight psychology program is stress management, including managing the stress response of airsickness, for students in the Euro-NATO Joint Jet Pilot Training (ENJJPT) program. Psychological assessments of flying personnel, air traffic controllers, and individuals being considered for special duties constitute a valuable contribution to aeromedical services. We present clinical vignettes to illustrate the interaction of the flight psychologist and aeromedical services, and the effect on flying training and flight safety.

Dislocation of the tarsometatarsal joints.

Problems in the diagnosis, reduction, and maintenance of reduction of dislocations of the tarsometatarsal joints are discussed. Many different patterns may present due to the anatomy of the foot and ankle and the different mechanisms of injury. Closed reduction and maintenance of reduction may be difficult to achieve, and open reduction may be required. Fixation with multiple K wires is useful in maintaining reduction. The possibility of vascular compromise should be kept in mind. Although anatomical reduction should be the goal of treatment, this does not always assure a painless foot. Arthrodesis for traumatic arthritis is rarely indicated but is a satisfactory salvage procedure.

Listeria monocytogenes cerebritis, bacteremia, and cutaneous lesions complicating hairy cell leukemia.

Hairy cell leukemia is a lymphoreticular malignancy characterized by a chronic course and multiple defects in host defense mechanisms. Infections are the major cause of morbidity and mortality in this malignancy. Opportunistic infections due to pathogens normally controlled by cell-mediated immune mechanisms have been increasingly described but have not included listerial infections. This report describes a case of disseminated Listeria monocytogenes infection including the uncommon manifestations of cerebritis and cutaneous lesions in a patient with hairy cell leukemia.

Lung mechanics, radiography and 67Ga scintigraphy in experimental Pneumocystis carinii pneumonia.

Respiratory system pressure-volume (P-V) studies, 67Ga-citrate scans, and chest radiographs were made in the corticosteroid-treated rat model of Pneumocystis carinii pneumonia. The steroid treatment used to provoke Pneumocystis infection in this model resulted in a reduction in body weight, lung weight and lung volumes compared to age-matched controls but no change in the normalized pressure-volume curve. P. carinii infection was associated with increased lung wet weight and flattening of the respiratory system P-V curve when compared to either age matched controls or steroid-treated animals on trimethoprim-sulfamethoxazole prophylaxis for P. carinii. Radiographs were interpreted as positive in only three of 11 animals with P. carinii, whereas 10 of 12 animals showed positive gallium-67 lung scans. We conclude that both gallium uptake and altered lung mechanics occur in the rat with Pneumocystis carinii and may reflect increased alveolar permeability and surfactant abnormalities noted in other studies.