Adjustment For Days Research Articles

Associations of dietary Provitamin A carotenoid intake with depressive symptoms in midlife women: Results from the study of Women's Health Across the Nation

BackgroundTo study the association of Provitamin A (pro-A) carotenoid intake from diet with depressive symptoms in midlife women. MethodsData for this cross-sectional study were retrieved from baseline assessment of the Study of Women's Health Across the Nation (SWAN). Logistic regression and restricted cubic spline models were performed to examine the association pro-A carotenoid intake with depressive symptoms. ResultsA total of 3054 midlife women aged 42–52 years were included in the present study. In overall midlife women, pro-A carotenoid intake was inversely associated with depressive symptoms (CES-D score ≥16). In premenopausal women, pro-A carotenoid intake was inversely associated with depressive symptoms after adjustment for age, race/ethnicity, total family income, education, physical activity, BMI, use of antidepressant, dietary total caloric, protein, carbohydrate, fat, vitamin C, vitamin E and pro-A carotenes in model 1. In fully adjusted model, after additional adjustment for day of cycle, FSH and SHBG, this association remained statistically significant. The fully adjusted odds ratios (ORs) with 95 % CI of depressive symptoms were 0.685 (0.450–1.043) in quartile 4 compared with quartile 1 for pro-A carotenoid intake. However, in early perimenopausal women, no statistically significant difference was observed between pro-A carotenoid intake and depressive symptoms after adjustment for confounders. LimitationsThis was a cross-sectional study, limiting causal inferences. Assessment of CES-D was based on a self-report scale. ConclusionPro-A carotenoid intake may be inversely associated with depression symptoms in premenopausal women, but not in early perimenopausal women.

173 The Bidirectional Relationships Between Sleep, Psychological Stress, and Negative Mood in Daily Life among Healthy Latinx Adults

Abstract Introduction While psychological stress is adversely linked to sleep, the bidirectional and temporal relationships between sleep and psychological stress in the context of daily life are largely understudied, particularly among Latinxs. We examined the bidirectional relationships between daily sleep duration, sleep quality, perceived stress, and negative mood in Latinx adults. Methods Between 2016-2019, healthy Latinxs (N=42), defined as those without any major physical or psychiatric morbidities, and free from polysomnography-assessed sleep disorders, were recruited from a community sample in New York. Participants naïve to study hypotheses completed 40 consecutive days of actigraphy and ecological momentary assessment of psychological stress and negative mood (depressed, anxious mood) using a 0 (not at all) to 10 (extremely) scale, contributing 1713 observations. Daily sleep duration was measured via wrist-actigraphy, and perceived daily sleep quality (1[very bad] to 4[very good]) was assessed via morning self-report. Sources of daily stress, including sociocultural stress, were collected once each evening. Multi-level modeling was used to examine within-person effects and temporal associations with adjustment for day of the week. Results Mean age=37.2 (SD=11.8), 69.1% women, 36.6% unemployed, 64.3% immigrant, and 38.1% Spanish-speaking. Non-specific stress (43%), work (28%), and family/relationship (21%) stress were the most common sources of daily stress. Discrimination and immigration stress were rarely reported as daily sources of stress (1.2%). Mean nightly sleep duration was 403.9 minutes (±81.3). Preliminary lagged linear mixed models indicated that a 60-minute increase in sleep duration during the night predicted a -.12 change in stress ratings (SE=.001,p<.0001) the next day, as well as -.06 change in anxious mood (SE=.001,p=.003). Better perceived sleep quality on a 4-point scale during the night predicted lower stress ratings (ß=-.11,SE=.05,p=.04) and less anxious mood (ß=-.13,SE=.05,p=.01) the next day. A one-point higher rating of depressed mood during the day predicted a -.03 decrease in perceived sleep quality that night (SE=.01,p<.05). Conclusion Overall, these results imply distinct associations of sleep with both anxiety and depressed mood. Longer sleep duration and improved perceived sleep quality were associated with subsequent decreased stress and anxiety. Increased depressed mood predicted worse sleep quality that night. Future research should identify the mechanisms of action for these differential associations. Support (if any):

Continuous low-dose antibiotic prophylaxis to prevent urinary tract infection in adults who perform clean intermittent self-catheterisation: the AnTIC RCT.

People carrying out clean intermittent self-catheterisation (CISC) to empty their bladder often suffer repeated urinary tract infections (UTIs). Continuous once-daily, low-dose antibiotic treatment (antibiotic prophylaxis) is commonly advised but knowledge of its effectiveness is lacking. To assess the benefit, harms and cost-effectiveness of antibiotic prophylaxis to prevent UTIs in people who perform CISC. Parallel-group, open-label, patient-randomised 12-month trial of allocated intervention with 3-monthly follow-up. Outcome assessors were blind to allocation. UK NHS, with recruitment of patients from 51 sites. Four hundred and four adults performing CISC and predicted to continue for ≥ 12 months who had suffered at least two UTIs in the previous year or had been hospitalised for a UTI in the previous year. A central randomisation system using random block allocation set by an independent statistician allocated participants to the experimental group [once-daily oral antibiotic prophylaxis using either 50 mg of nitrofurantoin, 100 mg of trimethoprim (Kent Pharmaceuticals, Ashford, UK) or 250 mg of cefalexin (Sandoz Ltd, Holzkirchen, Germany); n = 203] or the control group of no prophylaxis (n = 201), both for 12 months. The primary clinical outcome was relative frequency of symptomatic, antibiotic-treated UTI. Cost-effectiveness was assessed by cost per UTI avoided. The secondary measures were microbiologically proven UTI, antimicrobial resistance, health status and participants' attitudes to antibiotic use. The frequency of symptomatic antibiotic-treated UTI was reduced by 48% using prophylaxis [incidence rate ratio (IRR) 0.52, 95% confidence interval (CI) 0.44 to 0.61; n = 361]. Reduction in microbiologically proven UTI was similar (IRR 0.49, 95% CI 0.39 to 0.60; n = 361). Absolute reduction in UTI episodes over 12 months was from a median (interquartile range) of 2 (1-4) in the no-prophylaxis group (n = 180) to 1 (0-2) in the prophylaxis group (n = 181). The results were unchanged by adjustment for days at risk of UTI and the presence of factors giving higher risk of UTI. Development of antimicrobial resistance was seen more frequently in pathogens isolated from urine and Escherichia coli from perianal swabs in participants allocated to antibiotic prophylaxis. The use of prophylaxis incurred an extra cost of £99 to prevent one UTI (not including costs related to increased antimicrobial resistance). The emotional and practical burden of CISC and UTI influenced well-being, but health status measured over 12 months was similar between groups and did not deteriorate significantly during UTI. Participants were generally unconcerned about using antibiotics, including the possible development of antimicrobial resistance. Lack of blinding may have led participants in each group to use different thresholds to trigger reporting and treatment-seeking for UTI. The results of this large randomised trial, conducted in accordance with best practice, demonstrate clear benefit for antibiotic prophylaxis in terms of reducing the frequency of UTI for people carrying out CISC. Antibiotic prophylaxis use appears safe for individuals over 12 months, but the emergence of resistant urinary pathogens may prejudice longer-term management of recurrent UTI and is a public health concern. Future work includes longer-term studies of antimicrobial resistance and studies of non-antibiotic preventative strategies. Current Controlled Trials ISRCTN67145101 and EudraCT 2013-002556-32. This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment Vol. 22, No. 24. See the NIHR Journals Library website for further project information.

Particulate Matter and Risk of Hospital Admission in the Kathmandu Valley, Nepal: A Case-Crossover Study.

Air pollution is known to lead to a substantial health burden, but the majority of evidence is based on data from North America and Europe. Despite rising pollution levels, very limited information is available for South Asia. We investigated the impact of particulate matter with an aerodynamic diameter less than or equal to 10 μm (PM10) on hospitalization, by cause and subpopulation, in the Kathmandu Valley, an understudied and rapidly urbanizing region in Nepal. Individual-level daily inpatient hospitalization data (2004-2007) were collected from each of 6 major hospitals, as Nepal has no central data collection system. Time-stratified case-crossover analysis was used with interaction terms for potential effect modifiers (e.g., age, sex, and socioeconomic status), with adjustment for day of the week and weather. Daily PM10 concentrations averaged 120 μg/m3, with the daily maximum reaching 403 μg/m3. A 10-μg/m3 increase in PM10 level was associated with increased risks of hospitalization of 1.00% (95% confidence interval (CI): 0.62, 1.38), 1.70% (95% CI: 0.18, 3.25), and 2.29% (95% CI: 0.18, 4.43) for total, respiratory, and cardiovascular admissions, respectively. We did not find strong evidence of effect modification by age, sex, or socioeconomic status. These results, in combination with the high levels of exposure, indicate a potentially serious human health burden from air pollution in the Kathmandu Valley.

Genomic Profiling of Pharmacogenetic Variants Establishes a SNP-Based Predictor for Poor Outcome in Asian Children with Acute Lymphoblastic Leukemia (ALL): A Report from Malaysia-Singapore ALL Study Group

Despite successful application of risk-adapted treatment for pediatric ALL, about 20% of patients still relapse. And a substantial portion of such patients lack any conventional high-risk (HR) feature. As contemporary chemotherapy involves multiple drugs, treatment failure may attribute to the genetic variations in genes responsible for drug metabolism and transport. In this study, we established a SNP-based predictor to prognosticate patients enrolled on Malaysia-Singapore ALL 2003 (MS2003) and 2010 (MS2010) Studies.A cohort of 310 MS2003 patients was initially genotyped using Affymetrix DMET™ Plus Array. A nested Random Forests was designed to evaluate the association between the genotypes and cumulative incidence of relapse (CIR, including resistance). Shortlisted candidates were confirmed by competing risk regression adjusting for known prognostic factors. Such candidate SNPs were subsequently genotyped in additional 242 MS2003 patients and 106 MS2010 patients for further validation. A scoring metric indicating the number of relapse-associated genotypes in a patient was used to predict outcome. (Fig. 1)Of 1936 markers interrogated by DMET platform, 410 SNPs and InDels were eligible for downstream analyses after quality control. Random Forests identified 16 CIR-associated SNPs, 9 of which were verified in regression model and selected for further genotyping. Subsequent validation on all MS2003 patients (N=519) confirmed 3 risk genotypes that were associated with higher 5-yr CIR: A/A of rs4534 in CYP11B1 (P=3.10x10-3, HR=2.34 (95% CI 1.33-4.12)), C/T and T/T of rs1056837 in CYP1B1 (P=3.30x10-4, HR=2.66 (95% CI 1.56-4.53)), and T/T of rs3803390 in SLC28A1 (P=6.60x10-3, HR=2.18 (95% CI 1.24-3.82)). The number of risk genotypes was shown to strongly correlate with 5-yr CIR after adjusting presenting features including age, WBC and ALL subtype (P=6.70x10-8; Table 1). The risk was nearly 7-fold higher in patients with 2 risk genotypes compared to those without any risk genotype (P=2.00x10-8; Table 1 and Fig. 2a; there was no patient with all 3 risk genotypes). Further adjustment for Day 33 MRD did not alter the significance. Even in non-HR patients (without BCR-ABL1 fusion, MLL rearrangements, hypodiploidy, or Day 33 MRD>=1x10-2), this scoring metric remained significant (P=2.60x10-3 for incremental effect; P=1.20x10-3 for 2 risk genotypes vs. no risk genotype; Table 1 and Fig. 2b). Concordantly, increasing number of risk genotypes was also associated with a higher probability of Day 33 MRD-HR (i.e. MRD>=1x10-2; 6.5% of patients without any risk genotype vs. 9.8% of patients with 1 risk genotype vs. 29.0% of patients with 2 risk genotypes; P<0.001). In MS2010 patients, a similar trend was reproduced, showing a higher proportions of Day 33 MRD-HR (N=3, 33.3%) and adverse events (N=4, 44.4%) in patients with 2 risk genotypes (N=9). The 3-yr CIR was 22.2% (95% CI 2.8%-53.3%) in patients with 2 risk genotypes compared to 8.3% (95% CI 3.4%-16.0%) in others. Patients with 2 risk genotypes also had a significantly lower 3-yr EFS 55.6% (95% CI 20.4%-80.5%) compared to 90.6% (95% CI 81.5%-95.4%) in others (P=1.15x10-3).Our results suggest that germline variations can complement existing prognostic factors to refine risk stratification.Abstract 1069. Table 1Increasing number of risk genotypes was associated with 5-yr CIR in MS2003 cohort.Full cohort (N=519)Non-HR cohort (N=374)FrequencyHR (95% CI)PReproducibility (out of 100)*FrequencyHR (95% CI)PReproducibility (out of 100)*no risk genotype290ref.--212ref.--1 risk genotype1922.43 (1.29 - 4.58)5.90x10-3-1422.19 (0.84 - 5.70)0.11-2 risk genotypes376.87 (3.50 - 13.46)2.00x10-8-206.51 (2.10 - 20.14)1.20x10-3-Incremental effect-2.61 (1.84 - 3.69)6.70x10-899-2.51 (1.38 - 4.55)2.60x10-347* That adjusted significance (FDR=5%) is reproduced for more than 10 times is considered statistically significant according to binomial probability distribution (cumulative probability P(X¡Ý10)<0.05) [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Novel Description of the 24-Hour Circadian Rhythms of Brachial Versus Central Aortic Blood Pressure and the Impact of Blood Pressure Treatment in a Randomized Controlled Clinical Trial

Elevated brachial blood pressure (BP) is associated with increased cardiovascular risk and predicts morbidity and mortality in humans. Recently, 24-hour ambulatory BP monitoring and assessment of central aortic BP have been introduced to improve BP phenotyping. The Ambulatory Central Aortic Pressure (AmCAP) study combines these approaches and describes, for the first time, the diurnal patterns of simultaneously measured 24-hour ambulatory brachial and central pressures in a prespecified substudy embedded within a clinical trial of BP lowering in patients with hypertension. Twenty-four–hour ambulatory brachial and central pressure measurements were acquired using a tonometer mounted into the articulating strap of a wristwatch-like device (BPro) in 171 participants with hypertension recruited into the ASSERTIVE (AliSkiren Study of profound antihypERtensive efficacy in hyperTensIVE patients) trial. Participants were randomly assigned to BP lowering with either aliskiren 300 mg QD or telmisartan 80 mg QD for 12 weeks. Ambulatory brachial and central BP was measured in all participants both at baseline and at study end. Brachial and central BP both demonstrated typical diurnal patterns with lower pressures at night. However, night time was associated with smaller reductions in central relative to brachial pressure and decreased pulse pressure amplification ( P &lt;0.0001 for both). These effects were not modulated after BP lowering and were maintained after adjustment for day and night-time BP and heart rate ( P =0.02). This study demonstrates that brachial and central pressure show different diurnal patterns, which are not modulated by BP-lowering therapy, with relatively higher night-time central pressures. These novel data indicate that night-time central BP may provide prognostic importance and warrants further investigation. Clinical Trial Registration– URL: http://www.clinicaltrials.gov . Unique identifier: NCT00865020.

YEARS OF LIFE LOST DUE TO COLD AND HOT TEMPERATURES IN BRISBANE, AUSTRALIA

Background and Aims: Temperature is an important determinant of population health. Most previous studies were formulated in terms of temperature-related mortality risk, but it is also useful to consider years of life lost. Information on years of life lost is of great concern for policy makers, as evidenced by the issue of mortality displacement. This study aims to estimate the years of life lost associated with changes in season and temperature in Brisbane, Australia. Methods: We used daily time series data on climate and mortality collected for Brisbane city between 1996 and 2004. The years of life lost were estimated by matching each death by age and sex to Australian life tables for the years 2002–2004. Regression was used to estimate the association between daily total years of life lost and daily maximum temperature, with adjustment for day of week, trend and season. To examine the non-linear and lagged effects of temperature, we used the distributed lag non-linear model. Results: There was no effect of season on years of life lost. The association between daily maximum temperature and daily total years of life lost was V-shaped with increased years of life lost for cold and hot temperatures. The lowest years of life lost were at 30 °C for men and 27 °C for women. The greater heat-related years of life lost were most associated with a shorter lag (same day exposure), and the largest cold-related years of life lost were most associated with a multiple days lag. Conclusions: This study provides evidence of increased years of life lost due to cold and hot temperatures. Extreme temperatures are known to cause increases in the number of deaths, our study demonstrates that temperature extremes also cause significant increases in years of life lost.

Short Tag Noose Technique for Optional and Late Suture Adjustment in Strabismus Surgery

To present and evaluate a new technique that allows the second-stage suture adjustment in strabismus surgery to be skipped or delayed if the immediate postoperative alignment is satisfactory. The "short tag noose" technique replaces long sutures with short tags that can be left under the conjunctiva after adjustment. Retrospectively, the medical records of all patients treated by a single surgeon with this approach between January 1, 2005, and December 31, 2008, were evaluated for success rate (< or =10 prism diopters [PD] horizontal and < or =6 PD vertical), reoperation rate, and complications. Of 120 procedures reviewed, 27 (22.5%) were performed in children; 97 procedures (80.8%) were performed in patients with complex strabismus. Mean follow-up was 6 months. The success rate was 81.0% for horizontal strabismus and 70.7% for vertical strabismus at 2 months. The reoperation rate was 10.0% for horizontal strabismus and 19.0% for vertical strabismus. The noose slipped in 1 patient (0.8%) and was corrected by readjustment on day 4. Two patients (1.7%) required in-office excision of cysts or granulomas. The short tag noose technique simplifies the logistics of suture adjustment and avoids the need for sedation in children who do not require adjustment. It provides the ability to defer adjustment for days after surgery.

Diabetes and Cancer in Veterans of Operation Ranch Hand After Adjustment for Calendar Period, Days of Spraying, and Time Spent in Southeast Asia

The Air Force Health Study was launched in 1980 as part of a Federal effort to resolve the Agent Orange issue. To study diabetes and cancer with additional adjustment for days of spraying, calendar period of service, and time spent in Southeast Asia (SEA). This was a longitudinal study of veterans of Operation Ranch Hand, the unit responsible for spraying Agent Orange and other 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-contaminated herbicides in Vietnam from 1962 to 1971. Associations between TCDD and diabetes and between TCDD and cancer in Ranch Hand veterans are strengthened after adjustment for calendar period of service, days of spraying, and, for cancer, time spent in SEA. Calendar period of service, days of spraying, and time spent in SEA are important confounders in the Air Force Health Study.

New Chronic EEG Electrode for Critical/Intensive Care Unit Monitoring

The main limiting factor of EEG monitoring in the critical/intensive care environments is, and always has been, the recording electrode. The electrode and its application to the scalp has changed very little since EEG was first discovered and developed as a clinical tool. However, the evolution of amplifiers and data acquisition systems have made tremendous strides. Modern-day EEG recording systems now have the capability to record for days and weeks with little intervention, whereas the EEG electrode requires constant attention and skilled adjustment every 10 to 24 hours. If one surveys the vast array of electrodes used now and in the past, the only electrode that, once placed, never needed any further adjustment for days and weeks on end, was the chronic silver-silver/chloride (Ag-Ag/Cl) sphenoidal (Sp) electrode. This Sp electrode has now been modified to permit it to be placed subdermally, similar to that of a subdermal needle electrode, but now the needle is removed to leave in place a fine, flexible, durable, chronic Ag-Ag/Cl electrode. Once placed, this subdermal wire electrode (SWE, patent pending) starts to record immediately with a low impedance of 3 to 4 Komega. This electrode can record any biopotential, in humans and in animals, and in most recording environments; it never needs adjustment, and records high-quality biopotential signals for as long as it is left in place. The SWE is also MRI and computed-tomography compatible. It takes less than half the time to place the SWE, and placement can now be performed by any medically trained personnel to obtain a low-maintenance, high-quality EEG recording.

BODY MASS INDEX AND BROMOXYNIL EXPOSURE IN A SAMPLE OF RURAL RESIDENTS DURING SPRING HERBICIDE APPLICATION

Bromoxynil (3,5-dibromo-4-hydroxybenzonitrile), a phenolic herbicide, is widely used in production of cereals and other crops. Little is known, however, about bromoxynil exposure in humans. Results of previous research suggest a longer residence time in the body for bromoxynil compared to phenoxy herbicides [e.g., (2,4-dichlorophenoxy)acetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA)] and that bromoxynil would tend to partition into fatty tissue more so than 2,4-D. In previous research, body mass index (BMI) was found to be an independent predictor of plasma concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the persistent lipophilic metabolite of the chlorinated pesticide bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT). As part of the Prairie Ecosystem Study, gas chromatography/mass spectrometry analysis was used to measure concentrations of bromoxynil and seven other herbicides (2,4-D, dicamba, fenoxaprop, MCPA, ethalfluralin, triallate, and trifluralin) in plasma from residents (104 men, 88 women, 24 youths age 12–17yr) of a cereal-producing region in Saskatchewan, Canada, during spring herbicide application, 1996. Multiple logistic regression analysis was used to explore whether BMI predicted detection of bromoxynil in plasma from the adults. The prevalence of detection (detection limits: 2–50μg/L) was markedly higher for bromoxynil (men, 44.2%; women, 14.8%; youths, 20.8%) compared to each of the other herbicides including 2,4-D (men, 16.5%; women, 3.4%; youths, 12.5%) and MCPA (men, 6.8%; women, 1.1%; youths, 4.2%), although bromoxynil is commonly formulated or tank mixed with these herbicides. In the multiple logistic regression analysis, the variables BMI, exposure group [bromoxynil applicators, non-applicator family members of bromoxynil applicators, all others (reference group)], and days elapsed since the last use of bromoxynil were found to be independent predictors of detection of bromoxynil, while age, gender, and farm residency were not statistically significant. With adjustment for exposure group [bromoxynil applicators: odds ratio (OR=24.30, 95% confidence interval (CI)=9.59–61.58; nonapplicator family members of bromoxynil applicators: OR=3.53, 95% CI=1.19–10.44; all others (reference group)], the OR for detection of bromoxynil was 2.35 (95% CI=0.87–6.33) for participants in the middle (25.53–29.00kg/m2) tertile (men: OR=2.85, 95% CI=0.75–10.82; women: OR=1.63, 95% CI=0.36–7.40) of BMI and 4.01 (95% CI=1.46–11.03) for participants in the highest (>29.00kg/m2) tertile (men: OR=4.67, 95% CI=1.17–18.58; women: OR=2.20, 95% CI=0.44–10.99) with participants in the lowest (<25.53kg/m2) tertile as the reference group. Similar ORs were observed for BMI with adjustment for days elapsed since the last use of bromoxynil. In conclusion, further research is needed to investigate whether adiposity is an important modifying factor for persistence of bromoxynil in the body.

Air pollution and hospital admissions for ischemic heart disease in persons with congestive heart failure or arrhythmia.

We examined whether ischemic heart disease (IHD) hospital admissions were associated with air pollutants in those with and without secondary diagnoses of arrhythmia (ARR) or congestive heart failure (CHF). We assessed the occurrence of increased vulnerability among persons with these conditions to daily variations in ozone, carbon monoxide, nitrogen dioxide, or particulate matter less than or equal to 10 micro m in aerodynamic diameter (PM10). The study population consisted of members of a large health maintenance organization residing in the South Coast Air Basin of California from 1988 to 1995. After adjustment for day of week, study year, and smoothing splines for day of study, temperature, and relative humidity, CO and NO2 were both associated with admissions with the greatest effects for CO. A 1-ppm increase in 8-hr average CO was associated with a 3.60% [95% confidence interval (CI), 1.62-5.63%] increase in same-day IHD admissions in persons with a secondary diagnosis of CHF, a 2.99% (95% CI, 1.80-4.19%) increase in persons with a secondary diagnosis of ARR, and a 1.62% (95% CI, 0.65-2.59%) increase in IHD admissions in persons without either secondary diagnosis. Air pollution was most strongly associated with myocardial infarction hospital admissions. The vulnerability of the secondary CHF subgroup may be due to a greater prevalence of myocardial infarction primary diagnoses and not the modifying effect of CHF. This study suggests that people with IHD and accompanying CHF and/or ARR constitute a sensitive subgroup in relation to the effects of criteria ambient air pollutants associated with motor vehicle combustion.

A Method to Analyze Production Responses in Dairy Herds

Milk production was simulated in a 50-cow herd averaging 8182kg of 305-d milk with a standard deviation of 1364kg. Herd demographics were 35% first lactation, 20% second lactation, and 45% third or greater lactation cows. A lactation model was developed with the Wood's equation (Milk/d = A*DIM*e (;–c*dim)) to which random variation was added to be consistent with a coefficient of variation of 10% for daily milk production. Five sequential sampling periods, 30 d apart, were randomly selected for the experiment. For each of these sampling periods data were simulated for cow, lactation number, milk, and days in milk (DIM). To the third sampling period, a known input was pulsed into each cow record to simulate a change in milk production. Inputs and number of herds simulated were –1.140kg and 15 herds, 0.909kg and 30 herds, –0.455kg and 20 herds, 0kg and 65 herds, 0.455kg and 21 herds, –0.909kg and 47 herds, 1.140kg and 20 herds, and 2.270kg and 15 herds. Regression by cow was used to estimate milk production change for the known inputs: Milkijk = Intercept + betai*DIMij + TRTik + ɛijk. Parameter estimates for each cow were submitted to analysis of variance with herd as a class variable. The least square mean of TRT (dummy variable for known input of milk volume change) for herd was tested for difference from zero based on a “t” statistic. Herd responses were classed as negative, not different from zero, and greater than zero based on P<0.10. Herd responses were categorized based on the known input to assess the ability of the method to detect a change in production. The mean estimate of TRT from the regression analysis was used to assess the ability of the method to estimate the magnitude of the known input. The regression method was able to detect changes in production greater than 0.455kg, but is more useful when changes of 0.9kg or greater are shown. Adjustment for days postcalving on first test day is necessary to correct for the bias in linear regression to estimate response across the curvilinear milk production function.

Effect of Time of Onset of Rapid Cooling on Bovine Milk Fat Hydrolysis

Milk samples (n = 1818), collected from 261 cows, were used to evaluate effect of time of onset of rapid cooling on milk fat hydrolysis. Aliquots, either cooled immediately or after 1h at ambient temperarure, were analyzed for FFA content after storage at 4°C for 48h. Acid degree values for immediately cooled aliquots were higher than delayed cooled aliquots following adjustment for days in milk, days pregnant, milk yield, and SCC (.76 vs. .71). Correlation of .89 existed between aliquots; however, within a sample, aliquot response on cooling was variable in direction and magnitude. Immediate cooling enhanced lipolysis associated with increased days pregnant, decreased milk yield, and increased SCC. Consequently, effect of immediate cooling on milk fat hydrolysis was greater in milk collected from late lactation cows.

Hunter Movement and its Role in National Game Bird Surveys

AbstractAnalysis of sample survey data on the species composition of waterfowl kill for resident and nonresident hunters for provinces of Canada during 1974 and 1975 showed that a successful game bird hunter who hunted in more than one area (degree block) had both a higher average season kill and more successful days of hunting in which one or more birds were bagged, than one who hunted in the same area during the season. Adjustment for days hunted resulted in a higher daily hunting for those who hunted in more than one degree block. However, the higher kill of the successful hunter is attributable more to a larger number of days hunted than to a larger kill per successful day. Also, hunters hunting in more than one degree block had their successful hunting days more evenly spread across the season.The estimates of kill per successful hunter and days hunted for stratified sampling by areas of hunting were considerably more efficient than simple random sampling.

Milk production of quarter horse mares during 150 days of lactation.

Milk production was measured in fourteen Quarter Horse mares at seven stages of a 150-d lactation period. Mares were divided into two groups of seven and fed diets containing either soybean meal or soybean meal and urea as nitrogen supplements. Rations were isocaloric, contained approximately 12.5% crude protein and were fortified with vitamins and minerals. Daily milk yield was estimated by the weigh-suckle-weigh method and milk composition was determined from samples taken by hand milking. Average daily milk yield ranged from 11.8 kg in early lactation to 9.8 kg in late lactation. Differences (P less than .01) in milk yield due to number of previous lactations were observed. Also, diet influenced (P less than .01) milk yield, with mares fed soybean meal producing an average of 1.2 kg more milk/d than mares fed urea as part of the N supplement. Further, stage (day) of lactation influenced (P less than .01) daily milk yield. The largest mean daily milk yield was measured at approximately 30 d postpartum, but the predicted lactation curve was linear (P less than .05) over the range of observations in this study. Average percentages of total solids, protein and fat over the 150-d lactation were 10.5, 2.1, and 1.3, respectively. All components decreased significantly with advancing lactation. There was a trend toward a positive association between milk yield and solids content of the milk, but it was not significant. Milk yield was not significantly related to fat content of the milk. However, milk yield and protein content were correlated (r = .23; p less than .05). As expected, solids content of the milk was positively associated with percentages of protein (r = .59; P less than .01) and fat (r = .44; P less than .01). Relationships among milk components were similar after adjustment for days in milk. However, yield of milk and composition were unassociated (P less than .05) when days in milk were held constant.