Multi-year passive acoustic monitoring of coastal dolphins along the Israeli Mediterranean shallow shelf reveals the impact of marine fish farms and trawling patterns on their habitat utilization.

Dolphin preference and usage of various habitats along the Israeli shallow coastal shelf were investigated between 2019 and 2021 with passive acoustic monitoring devices. A hurdle model was used to examine the dolphins' visiting probability (chance of detection) and visit duration (length of stay once detected) across habitats, with diel cycle and season as explanatory variables. The influence of spatiotemporal prohibitions placed on trawler activity was also examined. It was found that dolphins exhibited higher presence in the vicinity of fish farms, up to three orders of magnitude, and even more so during periods when trawler activity was halted. The study also found a higher presence during the winter season and nighttime. Modeling did not find significant differences in the visiting probability or the visit duration between any non-farm-associated sites, including areas where trawling is prohibited. Further restrictions on the fishing industry may induce recovery of the benthic ecosystem and lower competition for resources, thus promoting higher dolphin presence in natural habitats along the shelf.

The utility of pregnancy associated plasma protein-A MoM values in prediction of term respiratory distress syndrome.

This study aimed to investigate if the pregnancy associated plasma Protein-A (PAPP-A) multiples of median (MoM) levels could be used as a marker for the early prediction of RDS. The present study was designed with data gathered from 1773 patients who were referred to our institution for first trimester fetal chromosomal anomaly screening. First trimester PAPP-A MoM values and postnatal RDS occurrences in these pregnancies were retrospectively analysed. Of the 1773 neonates that were included in the study, 28 were delivered at or beyond 37 weeks, and 42 were delivered less than 37 weeks of gestation. In the group of neonates at or beyond 37 weeks, the cut-off value for RDS prediction was determined as 1.02. For this cut-off value, sensitivity was 72.41% and specificity was 91.84%. The area under curve (AUC) was determined to be statistically significant (p < .01). In conclusion, it was determined that in neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values.IMPACT STATEMENTWhat is already known on this subject? Respiratory distress syndrome (RDS) is one of the major global healthcare problems, and continues to effect newborns despite the improvements in diagnosis and treatments of the disease. Studies have shown that pregnancy associated plasma protein-A (PAPP-A) has a critical role in cellular proliferation and differentiation, and it is closely associated with many physiological and pathological processes via regulation of local insulin like growth factor (IGF) concentrations. In majority of the past studies in the literature regarding PAPP-A values in pregnancies, the association between low values of PAPP-A MoM and maternal-fetal complications were investigated.What do the results of this study add? This study retrospectively examines the PAPP-A MoM levels and the occurence of RDS. In neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values which was measured at the first trimester fetal anomaly screening test.What are the implications of these findings for clinical practice and/or further research? In the light of these findings, in order to reduce RDS related neonatal morbidity and mortality, pregnancies with PAPP-A MoM values greater than 1.02 at the first trimester fetal anomaly screening should be more closely followed up and a higher rate of suspicion should be kept for RDS occurrence.

The Rough-Toothed Dolphin, Steno bredanensis, in the Eastern Mediterranean Sea: A Relict Population?

Only recently included among the cetacean species thought to regularly occur in the Mediterranean, the rough-toothed dolphin (Steno bredanensis) is an obscure and enigmatic member of this ensemble. Preliminary genetic evidence strongly indicates an Atlantic origin, yet the Mediterranean distribution for this species is conspicuously detached from the Atlantic, with all authenticated records during the last three decades being east of the Sicilian Channel and most within the bounds of the Levantine Basin. These dolphins are apparently a small, relict population, probably the remnant of a larger one, contiguous with that in the Atlantic and nowadays entrapped in the easternmost and warmest province. Abundance data are lacking for the species in the Mediterranean. Configuring acoustic detection software to recognise the apparently idiosyncratic vocalisations of rough-toothed dolphins in past and future acoustic recordings may prove useful for potential acoustic monitoring. Evidence accumulated so far, though scant, points to seasonal occupation of shallow coastal waters. Vulnerability to entanglement in gill-nets, contaminants in the region, and the occurrence of mass strandings (possibly in response to anthropogenic noise), are major conservation concerns for the population in the Mediterranean Sea.

Comparison of active vs. expectant management of the third stage of labor in women with low risk of postpartum hemorrhage: a randomized controlled trial.

OBJECTIVES: To compare the 'strictly' active management protocol in women with low risk of postpartum hemorrhage using the expectant management protocol with respect to changes in hematologic parameters, uterotonics, blood transfusions, or additional interventions. MATERIAL AND METHODS: A randomized controlled prospective trial in which 934 singleton parturients enrolled; 654 were randomly assigned to the active and mixed management groups. The primary outcome parameter was the reduction in hemoglobin concentrations due to delivery, and the secondary outcome parameters were changes in hemoglobin of more than 3 g/dL (ΔHb ≥ 3 g/dL), durations of the third stage of labor, need for additional uterotonic agents, blood transfusions, manual removal of the placenta, and surgical evacuation of retained products of conception. RESULTS: The mean postpartum hemoglobin concentration was significantly higher (P = 0.04) in the active management group with a significantly lower reduction (P = 0.03). Falls of hemoglobin levels of more than 3 g/dL (ΔHb ≥ 3g/dL) were less common in the active management group though not significantly (P = 0.32). The mean duration of the third stage of labor was significantly (P < 0.001) shorter in the active management group. There was no significant difference between the two groups with regard to the need for additional uterotonic agents, uterine atony, blood transfusion, manual removal of the placenta, surgical evacuation of retained products of conception, and prolonged third stage of labor. CONCLUSIONS: Although active management of the third stage of labor was associated with higher postpartum hemoglobin levels, it did not influence the risk of 'severe postpartum hemorrhage' in women with low risk of postpartum hemorrhage.

Dose dependent protective effects of vardenafil on ischemia-reperfusion injury with biochemical and histopathologic evaluation in rat ovary.

PURPOSE: The purpose of the study is to evaluate the effect of vardenafil on the histopathology and biochemical parameters in reducing damage in experimental ovarian ischemia and ischemia/reperfusion injury in a rat model and to compare the effect of two different doses of vardenafil. METHODS: Forty-two rats with experimental ovarian torsion. Group-I: sham; Group-II: ovarian ischemia; Group-III: 2 hours of ischemia followed by a 2-hour reperfusion. Group-IV: two hours before the sham operation, rats received 1mg/kg vardenafil; Group V and VI: A 2-hour period of ovarian ischemia was applied, in which rats were treated with intraperitoneal vardenafil 1 and 2mg/kg dose, after 1.5 hours of ovarian ischemia. After 2 hours of reperfusion, the ovaries on the right side were removed for examination. The ovarian ischemia/reperfusion injury was evaluated by calculating total antioxidant status, total oxidant status and oxidative stress index; and histopathologic examination of all ovarian rat tissue. RESULTS: The histologic findings in vardenafil treatment groups were statistically significant decreased edema and follicle degeneration, with vascular congestion, hemorrhage and follicle degeneration being dose-dependent. There were no statistically significant changes in the biochemical parameters. CONCLUSIONS: According to histopathological examination, low and high dose vardenafil is effective in attenuating ischemia-reperfusion induced ovary injury.

Is there a role for fetal ductus venosus and hepatic artery Doppler in screening for fetal aneuploidy in the first trimester?

OBJECTIVE: The aim of the present study was to evaluate the utility of ductus venosus (DV) and hepatic artery (HA) doppler in pregnant women who have high risk for aneuploidy in first trimester combined screening. METHODS: This prospective study was performed between February 2011 and February-2012, at a tertiary referral hospital. Singleton pregnancies with high risk for aneuploidy in combined screening test and normal nuchal translucency (NT) measurements were included in the study group. Measurements of DV Pulsatility Index of Veins (PIV) and HA Pulsatility Index (PI) were compared between the study group and controls. RESULTS: Within the study period, 104 women with singleton pregnancies were evaluated for DV and HA measurements and among these, 64 women met the inclusion criteria. A control group that comprised 40 women with similar gestational age, normal NT measurements and low-risk in first trimester combined tests was generated. DV-PIV measurements were significantly higher (p = 0.03), whereas HA-PI measurements were similar (p > 0.05) in women who had high-risk for aneuploidy in first trimester combined test. CONCLUSION: We concluded that the addition of DV-PIV and HA-PI measurements to the first trimester combined screening might increase the accuracy for Down syndrome detection.

Effect of maternal fasting for religious beliefs on fetal sonographic findings and neonatal outcomes.

OBJECTIVE: To investigate the effects of long-lasting maternal fasting on fetal biometry, amniotic fluid volume, fetal Doppler parameters, and neonatal outcomes. METHODS: The present study, conducted at Solhan State Hospital, Bingol, Turkey, between July and August 2013 recruited 82 healthy and otherwise normal pregnant women with a gestational age of 29 weeks or more who were fasting for at least 20 days. The control group comprised 87 healthy non-fasting women matched for maternal age, parity, gestational age. Fetal parameters were measured at the beginning and the end of the fasting month. Perinatal outcomes were compared between the groups. RESULTS: There were no significant differences between the groups in fetal biometry, fetal Doppler parameters, or neonatal outcomes. In the fasting group, however, there was a significantly greater decrease in amniotic fluid index during the fasting period (P<0.001). The number of women who initially had a normal amniotic fluid measurement and subsequently developed oligohydramnios was also significantly higher in the religious fasting group (P<0.05). CONCLUSION: Fetal development, Doppler parameters, and neonatal outcomes were not significantly affected in healthy fasting women; however, there was a significant association between fasting and amniotic fluid index. These findings mandate more frequent follow-up visits for this group of women.

Introducing a novel approach of network oriented analysis of ERPs, demonstrated on adult attention deficit hyperactivity disorder.

OBJECTIVE: Introducing a network-oriented analysis method (brain network activation [BNA]) of event related potential (ERP) activities and evaluating its value in the identification and severity-grading of adult ADHD patients. METHODS: Spatio-temporal interrelations and synchronicity of multi-sited ERP activity peaks were extracted in a group of 13 ADHD patients and 13 control subjects for the No-go stimulus in a Go/No-go task. Participants were scored by cross-validation against the most discriminative ensuing group patterns and scores were correlated to neuropsychological evaluation scores. RESULTS: A distinct frontal-central-parietal pattern in the delta frequency range, dominant at the P3 latency, was unraveled in controls, while central activity in the theta and alpha frequency ranges predominated in the ADHD pattern, involving early ERP components (P1-N1-P2-N2). Cross-validation based on this analysis yielded 92% specificity and 84% sensitivity and individual scores correlated well with behavioral assessments. CONCLUSIONS: These results suggest that the ADHD group was more characterized by the process of exerting attention in the early monitoring stages of the No-go signal while the controls were more characterized by the process of inhibiting the response to that signal. SIGNIFICANCE: The BNA method may provide both diagnostic and drug development tools for use in diverse neurological disorders.

Effect of isobaric breathing gas shifts from air to heliox mixtures on resolution of air bubbles in lipid and aqueous tissues of recompressed rats.

Deep tissue isobaric counterdiffusion that may cause unwanted bubble formation or transient bubble growth has been referred to in theoretical models and demonstrated by intravascular gas formation in animals, when changing inert breathing gas from nitrogen to helium after hyperbaric air breathing. We visually followed the in vivo resolution of extravascular air bubbles injected at 101 kPa into nitrogen supersaturated rat tissues: adipose, spinal white matter, skeletal muscle or tail tendon. Bubbles were observed during isobaric breathing-gas shifts from air to normoxic (80:20) heliox mixture while at 285 kPa or following immediate recompression to either 285 or 405 kPa, breathing 80:20 and 50:50 heliox mixtures. During the isobaric shifts, some bubbles in adipose tissue grew marginally for 10-30 min, subsequently they shrank and disappeared at a rate similar to or faster than during air breathing. No such bubble growth was observed in spinal white matter, skeletal muscle or tendon. In spinal white matter, an immediate breathing gas shift after the hyperbaric air exposure from air to both (80:20) and (50:50) heliox, coincident with recompression to either 285 or 405 kPa, caused consistent shrinkage of all air bubbles, until they disappeared from view. Deep tissue isobaric counterdiffusion may cause some air bubbles to grow transiently in adipose tissue. The effect is marginal and of no clinical consequence. Bubble disappearance rate is faster with heliox breathing mixtures as compared to air. We see no reason for reservations in the use of heliox breathing during treatment of air-diving-induced decompression sickness.

Forecasting epilepsy from the heart rate signal.

Information contained in the R-R interval series, specific to the pre-ictal period, was sought by applying an unsupervised fuzzy clustering algorithm to the N-dimensional phase space of N consecutive interval durations or the absolute value of duration differences. Data sources were individual, complex partial seizures of temporal-lobe epileptics and generalised seizures of rats rendered epileptic with hyperbaric oxygen. Forecasting success was 86% and 82% (zero false positives in resistant rats), respectively, at times ranging from 10 min to 30 s prior to seizure onset Although certain forecasting clusters predominated in the patient group and different ones predominated in the animal group, forecasting on the whole was seizure-specific. The high prediction sensitivity of this method, which matches that of EEG-based methods, seems promising. It is believed that an on-line version of the algorithm, trained on each patient's peri-ictal ECG, could serve as a basis for a simple seizure alarm system.

Effect of combined recompression and air, oxygen, or heliox breathing on air bubbles in rat tissues.

The fate of bubbles formed in tissues during the ascent from a real or simulated air dive and subjected to therapeutic recompression has only been indirectly inferred from theoretical modeling and clinical observations. We visually followed the resolution of micro air bubbles injected into adipose tissue, spinal white matter, muscle, and tendon of anesthetized rats recompressed to and held at 284 kPa while rats breathed air, oxygen, heliox 80:20, or heliox 50:50. The rats underwent a prolonged hyperbaric air exposure before bubble injection and recompression. In all tissues, bubbles disappeared faster during breathing of oxygen or heliox mixtures than during air breathing. In some of the experiments, oxygen breathing caused a transient growth of the bubbles. In spinal white matter, heliox 50:50 or oxygen breathing resulted in significantly faster bubble resolution than did heliox 80:20 breathing. In conclusion, air bubbles in lipid and aqueous tissues shrink and disappear faster during recompression during breathing of heliox mixtures or oxygen compared with air breathing. The clinical implication of these findings might be that heliox 50:50 is the mixture of choice for the treatment of decompression sickness.

Pulmonary oedema induced by strenuous swimming: a field study.

The purpose of the study was to document the incidence and recurrence rate of pulmonary oedema induced by strenuous swimming (SIPO), and to study the changes in relevant physiological parameters. Thirty-five young men were repeatedly examined over a 2-month period after a swimming time trial in the open sea. A tentative diagnosis of SIPO was made when the swimmer reported shortness of breath accompanied by cough. Twenty-nine events of SIPO were diagnosed in 21 individuals (60% incidence). Oxygen saturation was significantly reduced in SIPO. Mean forced vital capacity (FVC) and FEV(1) were significantly lower in the severe SIPO group. Also, mean FVC and mid-expiratory flows (FEF(25-75%)) obtained 12 months earlier during screening for the programme were lower in individuals who later had SIPO. The ratios of post-swim FVC and FEV(1) values to the corresponding selection examination values were lower in the severe SIPO group. Thus volumes decreased in the SIPO group, besides being lower at the start. Shortness of breath and coughing following strenuous swimming were related to hypoxaemia and reduction in lung volumes, suggesting pulmonary oedema. SIPO was a common and often recurrent phenomenon. Lower initial lung volumes and flows might predict future susceptibility to SIPO.

Forecasting generalized epileptic seizures from the EEG signal by wavelet analysis and dynamic unsupervised fuzzy clustering.

Dynamic state recognition and event-prediction are fundamental tasks in biomedical signal processing. We present a new, electroencephalogram (EEG)-based, brain-state identification method which could form the basis for forecasting a generalized epileptic seizure. The method relies on the existence in the EEG of a preseizure state, with extractable unique features, a priori undefined. We exposed 25 rats to hyperbaric oxygen until the appearance of a generalized EEG seizure. EEG segments from the preexposure, early exposure, and the period up to and including the seizure were processed by the fast wavelet transform. Features extracted from the wavelet coefficients were imputed to the unsupervised optimal fuzzy clustering (UOFC) algorithm. The UOFC is useful for classifying similar discontinuous temporal patterns in the semistationary EEG to a set of clusters which may represent brain-states. The unsupervised selection of the number of cluster overcomes the a priori unknown and variable number of states. The usually vague brain state transitions are naturally treated by assigning each temporal pattern to one or more fuzzy clusters. The classification succeeded in identifying several, behavior-backed, EEG states such as sleep, resting, alert and active wakefulness, as well as the seizure. In 16 instances a preseizure state, lasting between 0.7 and 4 min was defined. Considerable individual variability in the number and characteristics of the clusters may postpone the realization of an early universal epilepsy warning. University may not be crucial if using a dynamic version of the UOFC which has been taught the individual's normal vocabulary of EEG states and can be expected to detect unspecified new states.

Thermal status of wet-suited divers using closed circuit O2 apparatus in sea water of 17-18.5 degrees C.

A wet suit may not provide adequate thermal protection when diving in moderately cold water (17-18 degrees C), and any resultant mild hypothermia may impair performance during prolonged diving. We studied heat exchange during a dive to a depth of 5 m in sea water (17-18.5 degrees C) in divers wearing a full wet suit and using closed-circuit oxygen breathing apparatus. Eight fin swimmers dived for 3.1 h and six underwater scooter (UWS) divers propelled themselves through the water for 3.7 h. The measurements taken throughout the dive were the oxygen pressure in the cylinder and skin and rectal temperatures (Tre). Each subject also completed a cold score questionnaire. The Tre decreased continuously in all subjects. Oxygen consumption in the fin divers (1.40 l.min-1) was higher than that of the UWS divers (1.05 l.min-1). The mean total insulation was 0.087 degree C.m2.W-1 in both groups. Mean body insulation was 37% of the total insulation (suit insulation was 63%). The reduction in Tre over the 1st hour was related to subcutaneous fat thickness. There was a correlation between cold score and Tre at the end of 1 h, but not after that. A full wet suit does not appear to provide adequate thermal protection when diving in moderately cold water.

Susceptibility of the injured rat brain to CNS oxygen toxicity.

The possibility of an altered susceptibility of the injured brain to central nervous system (CNS) oxygen toxicity was examined in awake rats. Moderate to severe closed head injury with diffuse axonal damage was produced in anesthetized rats by the fluid percussion method (2-2.5 atm), after which chronic EEG electrodes were implanted. Twenty-four hours later, the rats were exposed to 5 atm abs (506.5 kPa) oxygen and the time to appearance of paroxysmal EEG patterns was noted. The difference between the 19 minute median latency of this group and 16 minute of a control group which underwent a sham operation did not reach statistical significance. Some injured animals convulsed with minimal or no EEG changes. The clinical implication could be that brain injured patients are not at higher risk of CNS oxygen toxicity but the EEG alterations that could potentially be used to forecast incipient convulsions, or be the indication of actual convulsions in the intact brain of a paralyzed patient, may not always be present.

CO2 retention during hyperbaric exercise while breathing 40/60 nitrox.

We evaluated CO2 retention in 24 Navy construction divers breathing air at 1 atm abs (101.3 kPa) and 40% O2 (40/60) nitrox at 4 atm abs (Po2 of 162.1 kPa) inside a pressure chamber. The divers sat immersed to the sternal notch and exercised against pneumatically loaded pedals at a Vo2 of approximately 1.3 liter/min. The mean end-tidal CO2 tension (PET(CO2)2) at 1 atm abs (45.7 +/- 5.0 SD torr) was significantly higher than that of non-divers and diving trainees (40 +/- 5.0) but did not increase significantly at depth (47.1 +/- 6.3). The ranking of CO2 retention was not maintained at depth. Unpredictable upward and downward shifts of up to 10 torr occurred in some divers. The PET(CO2) of six of the divers at pressure was greater than 50 torr, which based on animal studies markedly increases the risk of central nervous system oxygen toxicity. We translated their values into individual depth limits with 40/60 nitrox: three with 50 < PET(CO2) < 55 torr were forbidden to dive beyond 25 m and three with values > 55 torr were restricted to 20 m. We propose that whenever possible, PET(CO2) during exercise at pressure be measured in potential nitrox users and that the above PO2 limits be enforced on moderate and extreme CO2 retainers, respectively.

Effect of accumulation of CO2 on the survival of immature pigs in a confined atmosphere. A: Gas exchange.

Our purpose is to develop a survival strategy for man trapped in a confined space. We used immature pigs to assess the applicability of findings in rats for a larger mammal. The pig consumed oxygen in a sealed chamber until hypoxic collapse. We measured blood pressure, oxygen consumption, inspired O2 and CO2, minute ventilation, ECG and body temperatures, in three groups: no accumulation of CO2; CO2 level maintained at 5%, and maximal accumulation of CO2. Hypoxic oxygen consumption and ventilation were affected by the presence of CO2. Despite the pig's body mass being two orders of magnitude greater than that of the rat, its terminal PIO2 (35.9 torr) did not differ from that of the rat (35.3 torr). Accumulation of CO 2 had no significant effect on the terminal PIO2.

Effect of accumulation of CO2 on the survival of immature pigs in a confined atmosphere. B: Blood gas exchange.

As part of a study for developing survival strategy for humans in a confined space, we used immature pigs to assess the applicability of findings in rats and to evaluate the effect of body size. The cannulated unanesthetized animal was placed in a sealed chamber and depleted the oxygen until hypoxic collapse. Three groups were: no accumulation of CO2, CO2 maintained at 5%, and maximal accumulation of CO2. In hypoxia arterial and venous oxygen tension were higher in the pigs exposed to CO2 than in the no CO2 pigs. Oxygen extraction increased and oxygen transport decreased in hypoxia in the presence of CO2. Similarity in the P50 of the oxygen dissociation curve may explain the similar terminal PIO2 in the pig and the rat. There was a positive correlation between terminal PIO2 and terminal venous pH.

Recovery of the hypoxic ventilatory drive of rats from the toxic effect of hyperbaric oxygen.

Hyperbaric oxygen (HBO) exposure reduces the hypoxic ventilatory drive (HVD), probably by damaging the carotid bodies. The recovery of the HVD from HBO exposure was studied. The HVD was calculated from whole body plethysmographic recordings of the ventilatory response to greater than 85% and 2% O2 in N2 mixtures. Five groups of rats were exposed to HBO for 9 h at pressures of 1.9, 2.0, 2.1, 2.2, and 2.4 ATA, respectively. Each rat underwent three control measurements on different days prior to HBO exposures and then at various intervals following the exposure. Postexposure HVD was reduced to 28% of control values in the high PO2s. Ninety percent recovery of pre-exposure HVD was evident by 12-48 h although in some animals exposed to relatively low PO2s (1.9 and 2.0 ATA) HVD stabilized at a level lower than 100%. The recovery of the HVD in percent during the first 4 d following exposure can be expressed as an exponential function of the time from the termination of HBO: HVD = 28 + 72(1 - exp-0.053t) (t in hours). This information may be of importance in cases of repeated exposures to HBO where one tries to avoid cumulative damage to the carotid bodies, and in the care of the poorly oxygenated patient after HBO treatment.

Effects of dietary factors on antioxidant enzymes in rats exposed to hyperbaric oxygen.

To delineate the effect of dietary supplementation with vitamin E (Vit E) alone or in combination with riboflavin (Rib) or selenium (Se) or both, on biological oxidative damage in rat brain and lungs we exposed rats to hyperbaric oxygen (HBO) and measured the activities of glutathione reductase (GSSG-R), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G-6-PD) prior to or 48 h after exposure. Rats fed the dietary supplements, and a control group maintained on an unsupplemented diet, for 30 d, were each divided into 2 subgroups, of which 1 was exposed to 4.5 absolute atmospheres (ATA) of 100% oxygen for 30 min, hereafter referred to as "exposed". The remaining subgroups were left unexposed. Pre-exposure GSSG-R activity in brain was elevated in all experimentally fed groups (ranging from 23 to 84%) compared with the unexposed control, whereas GSH-Px, G-6-PD and SOD activities were unchanged. The lungs showed significant increases in pre-exposure GSSG-R, ranging from 15 to 28%, and GSH-Px, ranging from 13 to 23%, activities in all the groups fed the supplemental nutrients, except those on Vit E alone. Increases in G-6-PD activity were observed only in those fed supplements of Rib. In most cases exposure to oxygen caused an increase in GSSG-R, GSH-Px and G-6-PD activities. However the increases were higher in the supplemented groups.(ABSTRACT TRUNCATED AT 250 WORDS)