Youth screen use in the ABCD® study.

Adolescent screen usage is ubiquitous and influences development and behavior. Longitudinal screen usage data coupled with psychometrically valid constructs of problematic behaviors can provide insights into these relationships. We describe methods by which the screen usage questionnaire was developed in the Adolescent Brain Cognitive Development (ABCD) Study, demonstrate longitudinal changes in screen usage via child report and describe data harmonization baseline-year 2. We further include psychometric analyses of adapted social media and video game addiction scales completed by youth. Nearly 12,000 children ages 9-10 years at baseline and their parents were included in the analyses. The social media addiction questionnaire (SMAQ) showed similar factor structure and item loadings across sex and race/ethnicities, but that item intercepts varied across both sex and race/ethnicity. The videogame addiction questionnaire (VGAQ) demonstrated the same configural, metric and scalar invariance across racial and ethnic groups, however differed across sex. Video gaming and online social activity increased over ages 9/10-11/12 (p's < 0.001). Compared with boys, girls engaged in greater social media use (p < .001) and demonstrated higher ratings on the SMAQ (p < .001). Compared with girls, boys played more video games (p < .001) and demonstrated higher ratings on the VGAQ (p < .001). Time spent playing video games increased more steeply for boys than girls from age 9/10-11/12 years (p < .001). Black youth demonstrated significantly higher SMAQ and VGAQ scores compared to all other racial/ethnic groups. These data show the importance of considering different screen modalities beyond total screen use and point towards clear demographic differences in use patterns. With these comprehensive data, ABCD is poised to address critical questions about screen usage changes across adolescence.

Structural, compositional and electrochemical characterization of Pt-Co oxygen-reduction catalysts.

Pt-Co thin-film electrocatalysts have been characterized using low-energy ion-scattering spectroscopy (LEISS), X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), temperature-programmed desorption (TPD) and electrochemistry (EC). For comparative purposes, LEISS and EC were also carried out on a bulk Pt(3)Co(111) single crystal. The extensive experimental work resulted in the establishment of the surface phase diagram of the alloy film marked by a substantial divergence between the composition at the interface and that in the interior. When a dual-layer deposit of Pt and Co was annealed at high temperatures, alloy formation transpired in which the outermost layer became single-crystalline and enriched in Pt. The preferential surface segregation of Pt, however, was not sufficient to generate a platinum-only overlayer or "skin". Invariably, Co was found to co-exist with Pt, independent of the substrate [Mo(110) or Ru(0001)] employed; Pt(3)Co was the most favored composition. The same result, the absence of a Pt skin, was likewise indicated at the post-thermally-annealed surface of the bulk Pt(3)Co(111) monocrystal. For alloy-film surfaces more enriched in Pt than Pt(3)Co, the topmost layer was constituted primarily, but not exclusively, of Pt(111) domains. The proclivities of the alloys towards enhanced catalysis of the oxygen-reduction reaction were assessed in terms of their voltage efficiencies, as manifested by the open-circuit potential (OCP) in O(2)-saturated sulfuric acid electrolyte. The Pt(3)Co surface, whether from the thin film or the bulk single crystal, exhibited the highest OCP, a significant improvement over pure Pt but still appreciably lower than the thermodynamic limit. The degradation of the Pt(3)Co thin-film surface was predominantly due to Co corrosion. A minimal amount was spontaneously dissolved upon simple immersion in solution; slightly higher dissolution occurred at potentials above the OCP. The fraction that was not immediately corroded proved to be stable even after prolonged periods at potentials more positive than the OCP.

Changes in free amino acid profile of red snapper Lutjanus campechanus, eggs, and developing larvae.

The free amino acids (FAA) profile was determined for newly fertilized eggs and resultant larvae from wild-caught red snapper Lutjanus campechanus induced to spawn with hCG. Yolk sac and oil globule volumes of eggs and larvae were monitored over time from digital photographs. FAA profiles of the eggs and larvae were measured in picomoles (pmol) of FAA/mg of eggs by HPLC. Newly fertilized eggs had a mean total FAA content of 21.72 +/- 3.55 nmoles/egg (92.81 +/- 9.71 nmoles/mg eggs). Leucine, valine, lysine, and isoleucine were the most abundant essential FAA comprising 35.9% of the total FAA. Alanine, serine, asparagine, and glycine were the most abundant non-essential FAA comprising 34.2% of the total FAA. At 24 h post-hatch (hph) the mean total FAA had decreased by 81% since egg fertilization. The bulk of the FAA decrease was between the time of hatch and 12 hph. Only 8.5 +/- 1.5% of the initial concentration in fertilized eggs of isoleucine, 9.7 +/- 2.5% of arginine, and 9.9 +/- 2.0% of threonine remained at 12 hph. Among the non-essential FAA, alanine dropped the most by 12 hph with 4.6% of the concentration found in a recently fertilized egg remaining, while cysteine had increased 254.7 +/- 26.2%. The yolk sac volume decreased rapidly in the first 12 hph and was further reduced 77.0 +/- 2.5% from 12 to 24 hph. The oil globule depletion rate was a more linear decline from fertilized egg to 36 hph.

Enhancing venetoclax activity in acute myeloid leukemia by co-targeting MCL1.

Targeted therapies are frequently combined with standard cytotoxic drugs to enhance clinical response. Targeting the B-cell lymphoma 2 (BCL-2) family of proteins is an attractive option to combat chemoresistance in leukemia. Preclinical and clinical studies indicate modest single-agent activity with selective BCL-2 inhibitors (for example, venetoclax). We show that venetoclax synergizes with cytarabine and idarubicin to increase antileukemic efficacy in a TP53-dependent manner. Although TP53 deficiency impaired sensitivity to combined venetoclax and chemotherapy, higher-dose idarubicin was able to suppress MCL1 and induce cell death independently of TP53. Consistent with an MCL1-specific effect, cell death from high-dose idarubicin was dependent on pro-apoptotic Bak. Combining higher-dose idarubicin with venetoclax was able to partially overcome resistance in Bak-deficient cells. Using inducible vectors and venetoclax to differentially target anti-apoptotic BCL-2 family members, BCL-2 and MCL1 emerged as critical and complementary proteins regulating cell survival in acute myeloid leukemia. Dual targeting of BCL-2 and MCL1, but not either alone, prolonged survival of leukemia-bearing mice. In conclusion, our findings support the further investigation of venetoclax in combination with standard chemotherapy, including intensified doses of idarubicin. Venetoclax should also be investigated in combination with direct inhibitors of MCL1 as a chemotherapy-free approach in the future.

What weight loss treatment options do geriatric patients with overweight and obesity want to consider?

INTRODUCTION: Since the 1990s, a number of weight loss medications have been removed from the USA and or European market because of adverse events associated with these medications. These medications include fenfluramine (heart valve thickening), sibutramine (cardiovascular risk) and rimonabant (depression). This history may affect a patient's desire to consider weight loss medications as an option for weight management. OBJECTIVE: This descriptive study was designed to observe what treatment options the geriatric patient (age 65 or higher) seeking weight loss would like to consider, as well as the reasons they felt they struggled with overweight or obesity. METHODS: A questionnaire was given to 102 geriatric patients with overweight or obesity before starting a weight loss programme at a weight management centre. The questionnaire asked the patient why they felt they were overweight or obese and what treatment options they wished to consider. The geriatric patients were matched with younger patients in body mass index and sex. RESULTS: The three most common perceptions that geriatric patients felt were causes of their increased weight were 'lack of exercise' (76.2%), 'poor food choices' (59.4%) and 'cravings' (47.5%). When geriatric patients were asked what treatment options they would like to discuss, the four most common options requested were 'diet and healthy eating' (67.3%), weight loss medications (57.4%), a request for a 'metabolic work up' (55.4%) and 'exercise' (53.5%). These responses were no different from their younger cohorts. When geriatric patients with a body mass index of 35 or higher were given bariatric surgery as a treatment option, 21.9% marked it as a treatment option they would like to consider. CONCLUSIONS: Over half of geriatric patients desired to discuss weight loss medications as a treatment option. Diet and exercise were also of strong interest, which is in line with current weight management guidelines.

Studies of diabetic polyneuropathy using conduction velocity distribution (DCV) analysis.

The distributions of nerve fiber conduction velocities (DCVs) derived from the median nerves of 29 adult diabetic patients (mean age, 52.1 +/- 12.3 years) with mild or no symptoms or signs of polyneuropathy were compared with DCVs from 34 age-appropriate normal subjects. Ten patients (34%) had normal findings (type A DCVs). In the 19 patients (66%) with abnormal DCVs, defined as 10% or more of the DCV area falling outside the normal 95% confidence limits, two distinct patterns of DCV alteration were observed: type B DCVs (11 patients) showed reduced DCVmax, DCVmean, and DCVpeak, together with reduced DCVrange (narrow profile); whereas type C DCVs (8 patients) had reduced DCVmax, DCVmean, DCVpeak, and DCVmin, with normal DCVrange (broad profile). It is proposed that type C DCV represents a more advanced form of type B and that both reflect selective dysfunction of the fastest conducting (presumably largest-diameter) fibers in the nerve trunk. DCVmax was consistently greater than conventional measures of "maximal" CV in all patient subgroups. Patients with abnormal DCVs had higher incidence of mild neuropathic symptoms (15 of 19 versus 4 of 10, p less than 0.01) and greater insulin dependence (11 of 19 versus 1 of 10, p less than 0.001). Serial studies in 10 patients showed, at most, small degrees of change in conduction properties over relatively short intervals (1 to 9 months).

Use of cerebral evoked potentials to evaluate spinal somatosensory function in patients with traumatic and surgical myelopathies.

Cerebral somatosensory evoked potentials (SEP's) were elicited by electrical stimulation of the median nerve in the arm (SEPA) and of the posterior tibial nerve in the leg (SEPL) in 23 patients with incomplete localized lesions (including traumatic injuries, neoplasms, vascular malformations and infarcts) of the low cervical, thoracic, or lumbar spinal cord. In eight of 46 attempts (left and right sides), SEPL could not be recorded. Of the remaining 38 sides, spinal somatosensory conduction velocity (SSCV, indirectly estimated) was abnormally slow (less than 35 m/sec) in 20, and the amplitude of SEPL relative to SEPA (L:A ratio) was abnormally low (less than 0.5) in 20 (p less than 0.001 in each case, compared to normal controls). All three criteria yielded a combined 72% incidence of abnormality, correlating best with impairment of joint position sense. Serial postoperative studies in four cases documented an increase in the SSCV and L:A ratio following spinal decompression. These results demonstrate that the latency and amplitude characteristics of the cerebral SEP's from arm and leg permit quantitative evaluation of the functional status of the spinal somatosensory system.

Effects of steroids on the olfactory function of the dog.

Twenty-four (24) mature, mixed breed, healthy dogs weighing from 14.6 kg to 27.6 kg were used to study the effects of various steroids on the olfactory function of the dog using olfactory detection threshold as an index. Two odorants were used, viz; benzaldehyde and eugenol. Of the various steroids used, only dexamethasone produced classical signs of Cushing's syndrome in the dogs. However, all dogs that received either dexamethasone alone or hydrocortisone plus DOCA exhibited a significant elevation in the olfactory detection threshold for both odorants without any observable structural alteration of the olfactory tissue using light microscopy. On the other hand, neither DOCA, hydrocortisone alone, nor any of the vehicles used in the study significantly altered the olfactory function of the dogs. The results show that Cushing's syndrome can be experimentally produced in dogs using exogenous steroids and that this condition diminishes the olfactory capability of the dog without producing classical signs of the disease.

Effect of rainbow trout growth hormone complementary DNA on body shape, carcass yield, and carcass composition of F1 and F2 transgenic common carp (Cyprinus carpio).

The effect of rainbow trout growth hormone complementary DNA on body shape, dress-out yield, and body composition were assessed in the F1 and F2 generations of transgenic common carp (Cyprinus carpio). All measurements were compared with those for nontransgenic full-sibling common carp in their respective families, and the fish were communally evaluated in earthen ponds. The body weight and length were highly correlated (P <0.01) in both genotypes in all the families. Head morphometrics were negatively correlated (P <0.05) to weight and length of the fish. Various head, body, and caudal traits grew disproportionately faster in transgenic fish in both generations. The altered body shape of transgenic fish resulted in improved dressing percentage in the F2 generation. The carcass composition of transgenic muscle had a lower percentage of (P <0.01) moisture and lipids and higher (P <0.01) percentage of protein in both generations. Six of the 18 amino acids analyzed in F1 transgenic common carp muscle were higher F1 (P <0.05) than the control genotype; however, amino acid ratios were minimally changed. Also, the fatty acid profiles of both genotypes were minimally altered. Higher histidine and lysine ratios in the diet are recommended for maximum growth and health of transgenic common carp in intensive culture systems on the basis of essential amino acid ratios.

Event-related brain potentials differentiate normal and disabled readers.

Auditory event-related potentials (AERPs) recorded to irrelevant tone pairs while subjects performed visual, reading-related cognitive tasks differed significantly between normal and disabled readers. Disabled readers as compared with normal readers showed significantly lower amplitude right hemisphere AERP responses during tasks that involved visual-phonemic transfer of information and simple pattern recognition. Disabled readers as compared with normal readers also showed significantly higher amplitude left hemisphere responses during the visual-phonemic task. In both experimental conditions the reading-disabled subjects showed significantly lower amplitude right than left hemisphere AERP responses. Task-related strategies did not differ between groups. The pattern of AERP amplitude asymmetry found for disabled readers, which was opposite to that found for normal readers, suggests that the same reading-related tasks activated different cerebral processes in the two groups studied.

Effect of transportation stress on ovarian function in superovulated Hereford heifers.

A study was conducted to determine the effect of transportation stress on ovarian function in superovulated heifers. Thirty cyclic Hereford heifers of similar age and weight and in good body condition were randomly assigned to control and stress-treated groups. All animals received two daily injections of 5 mg follicle stimulating hormone (FSH) for 4 d beginning on Day 10 to 12 of the estrous cycle. A blood sample was collected at each FSH injection. On the fourth day of injections, heifers were given 25 mg prostaglandin F(2)alpha (PGF(2)alpha) in the morning and a second injection of 15 mg PGF(2)alpha in the afternoon. During superovulation, the stressed heifers were transported to a different location every 12 h whereas control animals remained at the pretrial site. Following 4 d of intermittent transporting and FSH treatment, stress-treated heifers were recombined with control animals. Ovaries were examined 8 d following the onset of standing estrus to determine length, width, thickness, and number of corpora lutea (CL). Peripheral plasma levels of cortisol were higher in the stressed group (P< 0.1). Least squares means for numbers of CL were 20.4 +/- 2.1 and 15.4 +/- 1.7 for control and treated heifers, respectively (P< 0.1). There were no treatment differences (P> 0.1) between length, width, or thickness of ovaries when the number of CL was held constant. These data suggest that stress of the type, intensity, and duration imposed in this study increased plasma levels of cortisol and reduced ovulation rate as determined by CL formation in superovulated heifers.

Secretion of PGF2alpha and oxytocin during hyperthermia in cyclic and pregnant heifers.

The effects of acute heat stress (HS) and oxytocin (OT) injection on plasma concentrations of PGF2alpha and OT were examined in cyclic (C; n = 15) and pregnant (P; n = 11) dairy heifers. On Day 17 of synchronized estrous cycles, animals were randomly assigned to either thermoneutral (TN; 20 degrees C, 20% RH) or HS (42 degrees C, 60% RH) chambers. The jugular vein of each heifer was cannulated and blood samples collected hourly for 4 h, then every 15 min for an additional 3 h. Oxytocin (100 IU) was injected (IV) 5 h after the start of blood collection. Plasma samples were assayed subsequently for concentrations of 13,14-dihydro-15-keto PGF2alpha (PGFM) and OT. During the 7-h experiment, body temperature of HS heifers reached 41.2 degrees C as compared to 38.5 degrees C in control heifers. Plasma concentrations of PGFM increased (P<0.05) and peaked 30 min after OT injection in C (890 pg/ml) and P (540 pg/ml) heifers. In C heifers, heat stress failed to alter PGFM concentrations either before or after OT injection. In the P group, PGFM concentrations following OT injection tended to be higher in HS heifers were further TN heifers (peak values of 690 vs. 410 pg/ml). Pregnant TN and HS heifers were further classified as responders or non-responders to OT challenge according to a cutoff value for PGFM of 193 pg/ml (overall mean of C heifers minus 1 SD). Five of six HS and one of five TN pregnant heifers were classified as responders (P<0.06). Oxytocin concentrations in plasma prior to injection of exogenous OT were not affected by HS or pregnancy status. It is concluded that in C heifers, acute HS in vivo does not cause any further rise in PGF2alpha secretion. However, in P heifers, HS appears to antagonize suppressive effects of the embryo on uterine secretion of PGF2alpha, as indicated by the larger proportion of P heifers responding to OT challenge.

Speech distortion measures for hearing aids.

Advances in digital technology and the associated introduction of new forms of distortion led us to investigate supplementary measures of electroacoustic distortion for hearing aids. Mathematical techniques were used to formulate a working model in which the hearing aid acts as a time varying linear filter. This model embodies an approach to separating distortion into perceptually relevant and irrelevant categories. Digitized speech was converted to analog form, routed through a commercial hearing aid, and the output of the aid was redigitized and stored. For a given input signal, output speech waveforms were then compared to the model output and performance measures were derived. Distortion was plotted in three dimensions to permit interpretation with respect to time, frequency, and amplitude. These results provide a more comprehensive and general format for the analysis of hearing aid distortion.

Effects of dietary protein on whole-body protein turnover and endocrine function in young-adult and aging dogs.

Thirty-six adult female Beagles averaging 2 (young-adult) or 8 (geriatric) yr of age were used to assess the effects of graded levels of dietary protein (16, 24, or 32%) on endocrine-controlled regulation of whole-body protein turnover. Rates of whole-body protein synthesis (WBPS) and whole-body protein degradation (WBPD) were estimated using orally administered 15N-glycine and total excreta collection. Although N balance was similar for all dogs, N flux through the metabolic pool increased linearly (P < 0.05) as protein intake increased. Rates of WBPS, WBPD, or the difference between them were not influenced by age (P > 0.10). A quadratic increase (P < 0.05) in WBPS and WBPD was observed in response to dietary protein. Serum insulin-like growth factor-I (IGF-I), IGF-I-binding protein 3, and total IGF-I-binding proteins were higher (P < 0.05) in geriatric dogs than in young-adult dogs regardless of protein intake. These results indicate that dietary protein in excess of 16% may not be required to maintain N balance in young-adult and aging dogs despite the linear increase in N flux through the metabolic pool. Furthermore, age-induced changes in endocrine functionality may differ between dogs and other species.

Growth performance and carcass traits of pigs subjected to marginal dietary restrictions during the grower phase.

Sixty-four individually housed pigs were used to investigate the effect of amino acid content of finisher diets on growth performance of pigs subjected to marginal dietary amino acid restrictions (80% of the 1988 NRC lysine recommendation) during the grower phase. In each of the two trials, low- and high-amino-acid grower diets (.421 and .765 g lysine/MJ DE, respectively) and four finisher diets (.421, .516, .612, and .707 g lysine/MJ DE) were randomly assigned within sex to 16 gilts and 16 castrated males weighing 23.0 +/- 2.0 kg in a 2 x 4 factorial arrangement of treatments. The average weight of pigs after a completion of diet change was 50.4 +/- 2.1 kg. All pigs were slaughtered at an average weight of 105.2 +/- 4.1 kg. Ultrasound backfat thickness was measured at the time of diet change and before slaughter. Pigs were allowed ad libitum access to feed and water. During the grower phase, pigs fed the high-amino-acid diet grew faster (P < .001) and more efficiently (P < .001) and had less ultrasound backfat (P < .001) than those fed the low-amino-acid diet. The grower diet had no effect on weight gain during the finisher phase. Consequently, pigs fed the high-amino-acid grower diet had better overall weight gain (P < .01) than those fed the low-amino-acid diet. The rate of lean accretion was, however, similar between the two groups of pigs. Furthermore, pigs fed the low-amino-acid grower diet seemed to have better carcass quality, as indicated by less ultrasound backfat (P < .01) and larger carcass longissimus muscle area (P < .05). Average and 10th rib carcass backfat decreased linearly (P < or = .05) and lean accretion rate improved linearly (P < .05) as the amino acid content of finisher diets increased, but there was no grower x finisher diet interaction in these and other response criteria. Although no evidence of compensatory weight gain was observed, it is possible that compensatory lean tissue growth may have occurred in pigs subjected to early amino acid restrictions at the expense of fatty tissue growth.

Developmental changes in the regulation of plasma growth hormone concentrations in Holstein calves.

A study was initiated to determine whether development of a functional ruminant digestive system was associated with alterations in plasma growth hormone (GH) concentration. Holstein bull calves were fed milk or milk with grain until studied at the age of 1 month (n = 12). Calves placed on pasture with some grain supplementation were studied at the age of 3 months (n = 6) to determine plasma GH concentration in an animal with fully developed ruminant metabolism. Blood samples were taken at 10-minute intervals for 5 hours, followed by administration of bovine GH-releasing factor (0.075 micrograms/kg of body weight) and subsequent blood sample collection for 1 hour. On the following day, a blood sample was collected via jugular cannula, clonidine (10 micrograms/kg) was administered, and blood samples were subsequently obtained. Data indicated that milk-fed calves had higher mean plasma GH concentration than did either milk/grain-fed or older calves. The difference in mean plasma GH concentration was related to higher secretory pulse amplitude. Pituitary responses to bovine GH-releasing factor did not differ among the 3 groups, but response to clonidine were greater in milk-fed calves than in calves of the other groups. These data indicate that the change from a nonruminant to a ruminant-type gastrointestinal tract, perhaps attributable to subsequent changes in metabolism, may induce changes in hypothalmic function to decrease GH concentration.

Developmental alterations in the regulation of glucagon and insulin secretion in Holstein calves.

Twenty-one Holstein bull calves were randomly assigned at birth to 3 groups. Two groups (each of 7 calves) were raised as follows: fed a milk diet alone or fed milk with grain supplementation after 2 weeks of age; studies were done when calves reached 4 weeks of age. The 3rd group was fed on milk with grain supplementation until weaning after which the calves were maintained on grain and pasture. These calves (older calves) were studied at 12 weeks of age. Either propionate (0.28 mmol/kg) or glucose (0.56 mmol/kg) was injected IV in a random order. Samples of blood were obtained from the calves before and immediately after injections were done and at 2, 5, 10, 15, 30, 45, and 60 minutes after secretagogue injection. Plasma was examined for glucose by a glucose oxidase procedure and for immunoreactive insulin (IRI) and glucagon (IRG) by radioimmunoassay. The IRI response to the injection of glucose was greater in older calves (P less than 0.02). Patterns of IRI secretion, as determined by heterogeneity of regression, showed age differences for both secretagogues (P less than 0.05). Base-line IRG was greater in milk/grain-fed calves than in milk-fed calves (P less than 0.05). Mean IRG response to propionate injection was higher (P less than 0.05) in milk/grain-fed calves than in milk-fed calves. Plasma glucose concentration increased in older calves, but decreased in milk-fed calves after propionate injection. The data indicate that maturation in the ruminant is accompanied by altered regulation of insulin and glucagon secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of large doses of ascorbic acid on performance, plasma calcium, bone characteristics, and eggshell quality in broilers and Leghorn hens.

Four experiments were conducted using broilers (Experiments 1 and 2) or White Leghorn hens (Experiments 3 and 4) to determine the effects of large doses of dietary ascorbic acid on performance, plasma concentration of total and ionic calcium, bone characteristics, and eggshell quality. A total of 564 male broilers were fed diets containing ascorbic acid (ranging from 0 to 3,000 ppm) from 3 to 7 wk of age. Weight gain and feed conversion were measured, and blood plasma was analyzed for total and ionic calcium. Leg bones (femur, tibia, and metatarsus) were analyzed for bone mineral content, density, and breaking strength. In Experiments 3 and 4, a total of 484 Leghorn hens were fed diets containing ascorbic acid (ranging from 0 to 3,000 ppm) for 4 wk. Egg weight and specific gravity were determined, and plasma and tibiae were analyzed as in Experiments 1 and 2. Results of the broiler experiment (Experiment 2) indicated that plasma ionic calcium was significantly increased (P < .05) in ascorbic-acid-treated birds. Among leg bones examined, femur strength was improved by 16% in birds fed 2,000 ppm of ascorbic acid (Experiment 2). Other bone characteristics were not affected. In the layer experiments (Experiments 3 and 4), egg weight increased up to 5% and egg specific gravity was improved in hens fed 2,000 or 3,000 ppm of ascorbic acid, which also had increased calcium in the blood. Results suggest that large doses of ascorbic acid in the diet influence calcium metabolism, affecting bone and eggshell mineralization in chickens.

A broad evaluation of B.t.i. for black fly (Diptera: Simuliidae) control in a Michigan river: efficacy, carry and nontarget effects on invertebrates and fish.

Efficacy for black fly control, carry and nontarget effects of B.t.i. (Teknar HP-D), applied in the Betsie River, Michigan, were studied in June 1988. Black fly mortality was high (approximately 100%) for a 2,200 m stretch downstream from the application site, declined to 30% at 3,200 m, and was nil at 4,500 m. Drift of black flies greatly increased after application at a downstream site, but did not change at an upstream site. There were no detectable nontarget effects of B.t.i. application on: 1) invertebrate macro- or micro-drift; 2) numbers of invertebrates in benthic Surber samples; 3) mortality or feeding of drifting and nondrifting insects; 4) growth or mortality of caged Stenomena sp. larvae; 5) invertebrate functional group composition; 6) mortality or weight change of caged rock bass; or 7) fish numbers, species composition, length-weight (rock bass only) relationships or rock bass diet. Sampling of Rheotanytarsus sp. midges on natural substrates indicated low (27%) mortality owing to B.t.i. at only 100 m downstream from the application site, with negligible mortality at all other downstream and upstream sites. This information, combined with no pronounced changes in numbers of midges in macro-drift after application, indicated that midge populations were not adversely affected by B.t.i. in the study.