Swimming behavior and prey retention of the polychaete larvae Polydora ciliata (Johnston).

The behavior of the ubiquitous estuarine planktotrophic spionid polychaete larvae Polydora ciliata was studied. We describe ontogenetic changes in morphology, swimming speed and feeding rates and have developed a simple swimming model using low Reynolds number hydrodynamics. In the model we assumed that the ciliary swimming apparatus is primarily composed of the prototroch and secondarily by the telotroch. The model predicted swimming speeds and feeding rates that corresponded well with the measured speeds and rates. Applying empirical data to the model, we were able to explain the profound decrease in specific feeding rates and the observed increase in the difference between upward and downward swimming speeds with larval size. We estimated a critical larval length above which the buoyancy-corrected weight of the larva exceeds the propulsion force generated by the ciliary swimming apparatus and thus forces the larva to the bottom. This modeled critical larval length corresponded to approximately 1 mm, at which, according to the literature, competence for metamorphosis and no more length increase is observed. These findings may have general implications for all planktivorous polychaete larvae that feed without trailing threads. We observed bell shaped particle retention spectra with a minimum prey size of approximately 4 microm equivalent spherical diameter, and we found that an ontogenetic increase in maximum prey size add to a reduction in intra-specific food competition in the various larval stages. In a grazing experiment using natural seawater, ciliates were cleared approximately 50% more efficiently than similar sized dinoflagellates. The prey sizes retainable for P. ciliata larvae covers the microplankton fraction and includes non-motile as well as motile prey items, which is why the larvae are trophically positioned among the copepods and dinoflagellates. Not only do larval morphology and behavior govern larval feeding, prey behavior also influences the feeding efficiency of Polydora ciliata.

Evaluation of the Myo armband for the classification of hand motions.

Pattern recognition-based control systems have been widely investigated in prostheses and virtual reality environments to improve amputees' quality of life. Most of these systems use surface electromyography (EMG) to detect user movement intentions. The Myo armband (MYB) is a wireless wearable device, developed by Thalmic Labs, which enables EMG recordings with a limited bandwidth (<100Hz). The aim of this study was to compare MYB's narrow bandwidth with a conventional EMG acquisition system (CONV) that captures the full EMG spectrum to assess its suitability for pattern recognition control. A crossover study was carried out with eight able-bodied participants, performing nine hand gestures. Six features were extracted from the data and classified by Linear Discriminant Analysis (LDA). Results showed a mean classification error of 5.82 ± 3.63% for CONV and 9.86 ± 8.05% for MYB with no significantly difference (P = 0.056). This implies that MYB may be suitable for pattern recognition applications despite the limitation in the bandwidth.

Synchronous, sustained oscillation of C-peptide and insulin in the plasma of fasting monkeys.

The previously reported synchronous oscillations in plasma glucose and insulin levels have been further studied to determine whether the phenomenon can be attributed to cyclic secretion or degradation of the hormone. Plasma C-peptide concentrations were measured and found to cycle with the same period as plasma insulin suggesting that the oscillations of insulin arise from changing secretion rather than degradation. The amplitude of C-peptide oscillation was 50 percent that of insulin. Assuming first order kinetics and the same relative rates of disappearance as in humans, this difference in amplitudes in consistent with equal secretion rates for the two peptides.

Effects of enteral and parenteral nutrition on appetite in monkeys.

Varied clinical observations of the presence of either hunger or anorexia during intragastric or intravenous alimentation have led to the current experiments. Nine rhesus monkeys (Macaca mulatta) were involved in studies of the long-term effects of enteral and parenteral nutrition on appetite as assessed by feeding behavior and gastric motility. The monkeys received either intragastric infusions of glucose or a complete liquid diet, or intravenous infusions of glucose or glucose/amino acid solutions. Oral intake was accurately adjusted to account for the calories administered by the intragastric route. Oral intake was also reduced in a calorically equivalent amount to account for the calories received during intravenous glucose. When glucose/amino acid solutions were administered parenterally, adjustments were less accurate, with resultant overeating and weight gain in some monkeys during parenteral nutrition, followed by prolonged suppression of appetite after cessation of the infusions. Further studies of the effects of varied compositions of parenteral nutrition, and varied methods of weaning from infusions, are indicated.

Subjective distresses of nasogastric tube feeding.

Health care professionals assume that tube feeding is an unpleasant, distressing experience for patients, which is only partially substantiated by experience. Thirty patients were interviewed via a tube feeding and hospital experience checklist (a 47-item interview schedule). Common experiences were operationally defined as those felt by at least 50%; subjectively distressful experiences were those identified by patients as causing distress. The most common and most distressful experiences of nasogastric tube feeding were: sensory irritations and sensory deprivation. The psychosensory irritation experiences were: thirst, sore nose or throat, dry mouth, runny nose, a tube in the nose, taking food through a tube, breathing through the mouth, breathing with a tube in the nose, taking food in a treatment type container, and taking food with a different texture and smell than usual. The psychosensory deprivation experiences were: an unsatisfied appetite for certain foods, deprivation of tasting, chewing, swallowing food, and drinking liquids, limited mobility, and deprivation of regular food. Except for burping, gastrointestinal symptoms were not common though they were usually distressful. This information has been used to develop teaching programs which are being tested for effectiveness in reducing distress associated with nasogastric tube feeding.

A randomized controlled trial on the effect of an information booklet for young families in Denmark.

The aim of the study was to describe young families' illness-behavior in connection with minor illness in children aged 0-8 years, and to assess the effect of delivered written health education. The effectiveness of written health education in the management of minor illness was evaluated by a randomized controlled trial. One hundred young families from one group practice were allocated at random to a study group and a control group. The study group received written health education. Health education resulted in more self-treatment and fewer contacts with the general practitioner (GP), and the families indicated worry less often as the main reason for consulting the GP. The GPs' assessment of the appropriateness of the families' consultations showed no significant differences between the study and the control groups. It is recommended that GPs, in connection with prophylactic child examinations, hand over a patient education manual. This manual could form the basis for a dialogue between the GP and the parents when their child becomes ill.

[The EMLA cream versus placebo in MMR vaccination of older children in general practice]. / EMLA-creme versus placebo ved MFR-vaccination af større børn i almen praksis. En dobbeltblind, randomiseret undersøgelse.

We investigated the effect of EMLA cream (active ingredients: 25 mg lidocaine and 25 mg prilocaine per gram of cream) on subjective experience of pain in connection with vaccination. The study was conducted as a double-blind, randomized, placebocontrolled trial in a general practice setting. The subjects were ten to fifteen year-olds, who were due to be inoculated with measles-mumps-rubella vaccine. Of the 118 children entering the trial, 117 completed the treatment (EMLA 58, placebo 59). Treatment time was at least 60 minutes for all children. The children reported similar degrees of pain immediately after vaccination in both groups, one third of both treatment and placebo groups reporting medium to strong pain (not significant). On the day after vaccination, more than half the families (59%) said that they would use the cream again in connection with future vaccinations; again, there was no statistically significant difference between the two groups in this respect. Based on these results, we conclude that use of EMLA cream as a topical local anaesthetic does not reduce the experience of pain in connection with the administration of measles-mumps-rubella vaccine to older children.

Acute illnesses in children. A description and analysis of parents' perception of illness threat.

OBJECTIVES: To identify families in which the parents reported the child's illness as particularly stressful (high perception of illness threat), and to find out which health problems the parents perceive as particularly threatening. DESIGN: The parents registered the diagnosis and perception of illness threat in relation to the child's latest illness within a four-week retrospective period. Selected psychosocial conditions of the families were recorded in the same questionnaire. SETTING: 18,949 families with at least one child under the age of 8 years, resident in the County of Ringkøbing in western Denmark at 1 March 1988. SUBJECTS: An age-stratified random sample of 1982 families was entered in the study. 85% of the families returned the questionnaire. RESULTS: There was a considerable variation in the parents' perception of illness threat. On the basis of a score it was possible to group parents with a high, medium, and low perception of illness threat. Every fourth family reported a high perception of illness threat. A multivariate analysis, with a high perception of illness threat as dependent and selected psychosocial conditions and the diagnosis as independent variables, led to the following main results: 1) parents with a high perception of the general health threat ("worried" parents) most frequently reported a high perception of illness threat, 2) the diagnoses were decisive; in particular, inflammation in the middle ear, bronchitis, pneumonia, and accidents led to the parents' reporting a high perception of illness threat, 3) parents without experience of children and children's illnesses more frequently perceived an actual illness as a high illness threat than parents with this experience, 4) parents more frequently perceive an illness in girls as a high illness threat. CONCLUSIONS: "Worried" parents, without experience of children and children's illnesses, perceive the child's latest illness as a high illness threat. These families need special care.

Acute illnesses in children. A description and analysis of the cumulative incidence proportion.

OBJECTIVES: To describe parent-reported morbidity in relation to the psycho-social conditions of the families and to characterize families whose children are frequently ill. DESIGN: The parent-reported morbidity in a two-month prospective period, and the psychosocial conditions of the families were registered by means of a questionnaire. The conditioned probability of parents' reporting an episode of illness was estimated by means of logistic regression analysis, taking the psycho-social conditions into consideration. SETTING: 18,949 families with at least one child under the age of 8 years, resident in the County of Ringkjøbing in western Denmark at 1 March 1988. SUBJECTS: An age-stratified random sample of 1982 families was entered in the study. 1588 (82%) families returned the questionnaire. RESULTS: The parents reported considerable morbidity in their children. The cumulative incidence proportion (CIP) for the period was 48%. The multivariate analysis of the parent-reported morbidity led to the following main results: 1) the morbidity was greatest for children aged 6 to 18 months, after which it decreased with age, 2) there was interaction between the care conditions and the child's age--CIP for children up to two years was largest for the children who were cared for in daycare, while the CIP for the older children was largest for the children who were cared for at home, 3) if the parents reported that the child's siblings suffered from chronic or frequently recurring morbidity, the child's morbidity rate was significantly increased, 4) mothers with higher education reported more morbidity in their children than mothers without this education, and 5) parents with a high perception of the general health threat ("worried" parents) reported more morbidity than did parents with a low perception. CONCLUSIONS: The results made it possible to characterize families whose children were frequently reported ill.

Regulation of appetite during total parenteral nutrition.

To study effects of total parenteral nutrition (TPN) on appetite, in an effort to obtain an objective assessment of hunger separated from underlying pathology, caloric intake and levels of TPN were measured in two male rhesus monkeys. TPN was found to affect appetite by reducing voluntary food intake. One monkey showed precise regulation of daily oral caloric intake and maintained stable body weight during this period. The other monkey did not show such precise regulation. When TPN was stopped, both continued suppression of oral intake for a time. Implications are discussed.

Mesocosm study of Mytilus edulis larvae and postlarvae, including the settlement phase, exposed to a gradient of tributyltin.

In a mesocosm study, the effects of a gradient of tributylin (TBT) (nominal TBT concentrations of 0.3, 2.3, 18.5, 146, and 1150 ng Sn liter-1) on Mytilus edulis larvae and postlarvae, including the settlement phase, were investigated over 15 days. Effects of TBT on mortality, growth measured as increase in shell length, shell dimensions, and settlement were evaluated. In general, mortality was high in all mesocosms including the control; during the first 24 h of the experiment, mortality was 63% at the highest TBT concentration (26% in the control). An LC50 (24 h) of 254 ng Sn liter-1 was estimated. The mortality rate of larvae/postlarvae increased 40% at 18.5 ng Sn liter-1 (0.41 day-1) compared with the control (0.30 day-1). For postlarvae, the growth rate decreased with increasing TBT concentration. The mean shell length at 2.3 ng Sn liter-1 was significantly reduced in comparison to the control on Day 15. Then EC10 (15 days) for shell growth was estimated to be 5.4 ng Sn liter-1. This is the lowest effect concentration ever reported in the literature. For postlarvae, shell dimensions in terms of shell length-shell width relations were affected by TBT at 1150 ng Sn liter-1, because the reduced growth led to the failure of adult mussels to secret a dissochonch shell. During the first days of exposure, the settlement monitored on polyethylene settling strips was stimulated by TBT, after which the settlement decreased due to the high mortality. Only a small portion of the population survived to the end of the test period. By comparison of the biotic conditions (in terms of larval abundance and particle concentration reflecting larval food) in the control mesocosm with those in the cove where the experiment was conducted, it was concluded that the mesocosm had successfully simulated the field conditions.