Nutrient and sediment removal by stormwater biofilters: a large-scale design optimisation study.

A large-scale column study was conducted in Melbourne, Australia, to test the performance of stormwater biofilters for the removal of sediment, nitrogen and phosphorus. The aim of the study was to provide guidance on the optimal design for reliable treatment performance. A variety of factors were tested, using 125 large columns: plant species, filter media, filter depth, filter area and pollutant inflow concentration. The results demonstrate that vegetation selection is critical to performance for nitrogen removal (e.g. Carex appressa and Melaleuca ericifolia performed significantly better than other tested species). Whilst phosphorus removal was consistently very high (typically around 85%), biofilter soil media with added organic matter reduced the phosphorus treatment effectiveness. Biofilters built according to observed 'optimal specifications' can reliably remove both nutrients (up to 70% for nitrogen and 85% for phosphorus) and suspended solids (consistently over 95%). The optimally designed biofilter is at least 2% of its catchment area and possesses a sandy loam filter media, planted with C. appressa or M. ericifolia. Further trials will be required to test a wider range of vegetation, and to examine performance over the longer term. Future work will also examine biofilter effectiveness for treatment of heavy metals and pathogens.

The influence of temperature on nutrient treatment efficiency in stormwater biofilter systems.

Nutrients can cause eutrophication of natural water bodies. Thus, urban stormwater which is an important nutrient source in urbanised areas has to be treated in order to reduce its nutrient loads. Biofilters which use soil filter media, biofilms and plants, are a good treatment option for nutrients. This paper presents the results of a biofilter column study in cold temperatures (+2 degrees C, +8 degrees C, control at +20 degrees C) which may cause special problems regarding biofilter performance. It was shown that particle-bound pollutants as TSS and a high fraction of phosphorus were reduced well without being negatively influenced by cold temperatures. Nitrogen, however, was not reduced; especially NO(x) was produced in the columns. This behaviour can be explained with both insufficient denitrification and high leaching from the columns.

Update on the epidemiology, diagnosis, and treatment of posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) is a maladaptive, pathological response to a traumatic event which is currently underdiagnosed and undertreated. This results in part from a lack of awareness regarding the prevalence of the disorder. It has been estimated that at least one third of the general population will be exposed to severe trauma throughout their lifetime, out of which approximately 10 % to 20 % develop PTSD. A prevalence of 3 % to 6 % of PTSD in the general population, found in several studies, corresponds well with these figures. Both the type of trauma and the personal characteristics of the individual involved are associated with the probability of developing PTSD. The Diagnostic and Statistical Manual of Mental Disorders, 4th ed (DSM-IV) gives four diagnostic criteria: (i) exposure and emotional response to a traumatic event; (ii) reexperiencing; (iii) avoidance; and (iv) increased physiological arousal, along with severe impairment in occupational, social, and interpersonal functioning. The rate of comorbidity with other mental disorders is high, particularly for major depression, anxiety disorders, and substance abuse. Different types of psychological intervention, including cognitive-behavioral therapy and a host of pharmacological interventions, have been tried. Selective serotonin reuptake inhibitors (SSRIs) are currently the most widely researched agents with consistent, though modest, therapeutic effects. Other compounds, such as tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) have also been found to be effective, although their use is limited due to side effects. PTSD is a psychobiological phenomenon in response to psychological trauma, which represents maladaptive neurobiological deregulation and psychological dysfunction, and awaits further recognition and research.

Elevated awaking thresholds during sleep: characteristics of chronic war-related posttraumatic stress disorder patients.

BACKGROUND: Sleep disturbances are one of the hallmarks of posttraumatic stress disorder (PTSD); however, sleep laboratory studies have provided inconsistent evidence of the existence of objective sleep disturbances in PTSD patients. Reports that awaking thresholds from sleep in war-related PTSD patients were significantly elevated compared to normals are discordant with complaints of insomnia. The present study investigated the relationship between awaking threshold from REM sleep in war-related PTSD patients and their dream recall, dream content, and clinical condition. METHODS: After informed consent was obtained from 12 PTSD patients and 12 controls, they were investigated by polysomnographic recordings for 4 nights. Awaking thresholds to clicks were determined during 1 night, and dreams were collected during 2 nights. Patients' symptoms were assessed by the Zung and Beck depression scales, Impact of Events Scale, State and Trait Anxiety, and Symptom Check List questionnaires. RESULTS: Although there were no significant differences between sleep data of patients and controls, PTSD patients had significantly higher awaking thresholds. Awaking thresholds were significantly positively related to depression and anxiety scores. Patients' dreams were significantly more aggressive and hostile, and in 6 patients they included explicit war-related contents. The severity of the clinical picture was significantly related to the dreams' scores of aggression-hostility, and to sleep quality variables. CONCLUSIONS: Elevated awaking thresholds from sleep are a characteristic finding in chronic war-related PTSD patients, which may help to explain the diverse sleep laboratory findings in this syndrome.

Actigraphic sleep monitoring in posttraumatic stress disorder (PTSD) patients.

Posttraumatic stress disorder (PTSD) patients frequently complain that they suffer from sleep disturbances. To date, the polysomnographic studies that have attempted to study PTSD patients' subjective complaints of sleep difficulties have produced conflicting results. The objective of the present study was to compare PTSD patients' subjective complaints of poor sleep and objective actigraphic recordings of their sleep over a period of several consecutive nights. The results indicate that PTSD patients do not suffer from poorer sleep than a control group, based on actigraphic measures, and that their subjective sleep evaluation is inconsistent with objective sleep measures. These patients fail to correctly estimate their sleep.

Event-related potentials in post-traumatic stress disorder of combat origin.

Visual event-related potentials (ERPs) of primary interest in this study of post-traumatic stress disorder (PTSD) were N1, N2, P2, and P3. Forty Israeli combat veterans consisting of 20 PTSD sufferers and 20 normal controls were evaluated. ERPs were recorded in response to three sets of computer-generated visual stimuli, presented in the form of a modified oddball paradigm. These stimuli included: domestic animal pictures (targets), emotionally neutral pictures of furnishings (nontargets), and combat-related pictures (nontarget probes). Subjects were required to discriminate between target and nontarget stimuli by pressing a button in response to target stimuli only. Subjects were instructed to ignore all nontarget stimuli. As expected, target stimuli evoked accentuated P3 amplitudes in both controls and PTSD patients. The nontarget combat-related pictures elicited enhanced P3 and N1 amplitudes in the PTSD patients only. N2 amplitudes were accentuated in PTSD patients for both targets and combat-related pictures. P3 latencies and reaction times to target stimuli were prolonged in PTSD patients. The same tendency was observed for N1 latencies. These results may indicate that an altered state of early and late cognitive selective attention processing exists in PTSD patients in addition to a vulnerability to traumatic reminiscences.

[Psycho-neuro-physiological assessment of post-traumatic stress disorder using event-related potentials].

To evaluate certain aspects of cognitive processing in posttraumatic stress disorder (PTSD), brain event-related potentials, primarily P300, to traumatic stimuli were recorded. 20 Israeli veterans with PTSD of combat origin and matched controls were studied. In a modification of the oddball paradigm, subjects were asked to react to target pictures of traumatic combat-related subjects while ignoring non-target pictures of irrelevant subjects. PTSD patients reacted with an accentuated P300 and prolonged reaction times to the traumatic pictures. In addition, P300 and reaction times to the target pictures were prolonged in PTSD patients as compared to controls. Event-related potentials (P300) to traumatic stimuli can serve as an objective and accurate brain parameter for characterization and diagnosis of PTSD. In addition, it contributes to understanding the pathogenesis of PTSD as a specific impairment in information processing.

Benign synovitis of the hip in adults.

Hip synovitis plays a part in many rheumatic diseases. In the young adult acute arthritis may be due to reaction to trauma, infection or gout. Although transient synovitis of the hip is a well-known phenomena in children the condition is not well-documented in adults. We present 10 young adults with idiopathic transient synovitis of hip who had attended the Soroka Medical Centre between 1986 and 1990.