Effect of divergence in phenotypic residual feed intake on methane emissions, ruminal fermentation, and apparent whole-tract digestibility of beef heifers across three contrasting diets

This study aimed to examine the effect of divergent phenotypic ranking for residual feed intake (RFI) on ruminal CH emissions, diet digestibility, and indices of ruminal fermentation in heifers across 3 commercially relevant diets. Twenty-eight Limousin × Friesian heifers were used and were ranked on the basis of phenotypic RFI: 14 low-RFI and 14 high-RFI animals. Ruminal CH emissions were estimated over 5 d using the SF tracer gas technique on 3 successive occasions: 1) at the end of a 6-wk period (Period 1) on grass silage (GS), 2) at the end of an 8-wk period (Period 2) at pasture, and 3) at the end of a 5-wk period (Period 3) on a 30:70 corn silage:concentrate total mixed ration (TMR). Animals were allowed ad libitum access to feed and water at all times. Individual DMI was estimated during CH measurement and rumen samples were taken at the end of each CH measurement period. Diet type affected all feed intake and CH traits measured ( < 0.01) but was unavoidably confounded with animal age/size and experimental period. Correlation coefficients between RFI and DMI were significant ( < 0.05) only when animals were fed the TMR. Daily CH correlated with DMI ( = 0.42, < 0.05) only when animals grazed pasture. Daily DMI was lower in low-RFI animals ( = 0.047) but only when expressed as grams per kilogram metabolic BW. Absolute CH emissions did not differ between RFI groups ( > 0.05), but CH yield was greatest in low-RFI heifers ( = 0.03) as a proportion of both DMI and GE intake. Interactions between the main effects were observed ( < 0.05) for CP digestibility (CPD), DM digestibility (DMD), ruminal propionate, and the acetate:propionate ratio. Low-RFI animals had greater ( < 0.05) CPD and DMD than their high-RFI contemporaries when offered GS but not the other 2 diets. Low-RFI heifers also had greater OM digestibility ( = 0.027). Additionally, low-RFI heifers had a lower concentration of propionate ( < 0.05) compared with high-RFI heifers when fed GS, resulting in a greater ( < 0.05) acetate:propionate ratio. However, these differences were not evident for the other 2 diets. Energetically efficient animals do not have a lower ruminal methanogenic potential compared with their more inefficient counterparts and, indeed, some evidence to the contrary was found, which may reflect the greater nutrient digestive potential observed in low-RFI cattle.

Diet composition at weaning affects the rumen microbial population and methane emissions by lambs

The aim of this experiment was to investigate whether different diets at weaning determine the microbial populations established in the rumen, together with its methanogenic capacity, and whether these differences are consistent over a longer time period. Twenty ewes with single lambs were used in two periods. Period I: 10 lambs had access only to grass hay whilst with the dam and for 8 weeks after weaning (group H). The other 10 lambs had free access to concentrate and grass hay whilst with the dam and were fed with a 60 : 40 mix of concentrate and grass hay for 8 weeks after weaning (group C). Eight weeks after weaning, methane emissions were measured in polycarbonate chambers over a 3-day period. After methane emission measurements, five lambs from each group were randomly selected and slaughtered and samples of rumen content collected for measuring rumen fermentation parameters and for microbial enumeration (total and cellulolytic bacteria and methanogenic archeaea) by most probable number. Period II: the remaining 10 lambs were grouped together and fed the same diet (grass and concentrate) for 4 months. After this period, all animals were fed concentrate and grass hay (60 : 40) for 2 weeks and introduced in to the chambers to measure methane emissions over a 3-day period. After measurements, they were slaughtered and rumen samples collected and analysed as in Period I. Lambs from group H produced more (P = 0.04) methane than group C lambs (26.0 v. 22.5 L/kg DM intake) in Period I. Group H lambs also had less total bacteria (10.2 × 1010 v. 61.6 × 1010 cells; P = 0.284) but more cellulolytic bacteria (40.6 × 109 v. 10.0 × 109 cells; P = 0.098) and methanogenic archaea (37.1 × 109 v. 19.0 × 109 cells; P = 0.113) than group C lambs in Period I. The acetate to propionate ratio tended to be higher (P = 0.089) in group H lambs than in group C lambs (3.00 v. 2.35). In Period II, methane produced was not different (P > 0.05) between the groups (26.6. v. 25.7 L/kg DM intake by group C and H lambs, respectively). Microbial numbers and fermentation parameters were also similar in samples collected from both experimental groups in Period II. Our results show that the differences observed as a result of providing different diets at weaning disappear in the long-term. It may be appropriate to study a wider range of dietary treatments to better understand the factors determining the microbial populations establishing in the rumen.

Improved molecular diagnosis of dystrophinopathies in an unselected clinical cohort

Mutations in the DMD gene result in Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Readily available clinical tests detect only deletions of one exon or greater, which are found in approximately 60% of cases. Mutational analysis of other types of DMD mutations, such as premature stop codons and small frameshifting insertions or deletions, has historically been hampered by the large size of the gene. We have recently reported a method that allows the rapid and economical sequencing of the entire coding region of the DMD gene, and that is more sensitive than methods based on single-strand conformational polymorphism (SSCP) screening or other preliminary screening steps. Here we use single condition amplification/internal primer (SCAIP) sequencing analysis, in combination with multiplex amplifiable probe hybridization (MAPH) analysis of duplications, to report the frequency of mutations in a large cohort of unselected dystrophinopathy patients from a single clinic. Our results indicate that 7% of dystrophinopathy patients do not have coding region mutations, suggesting that intronic mutations are not uncommon. The availability of rapid and thorough mutation analysis from peripheral blood samples, along with an improved estimate of the percentage of non-coding region mutations, will be of benefit for improved genetic counseling and in identification of cohorts for clinical trials.

Swim-trained rats have greater bone mass, density, strength, and dynamics

Weight-bearing exercise is traditionally recommended for improving bone health in postmenopausal women. Effects of swim exercise were studied as an alternative to weight-bearing exercise in ovariectomized rats. Rats in a swim group (Sw, n = 8) swam for 12 wk, 5 days/wk for 60 min per session. A control group (Con, n = 9) engaged in no structured exercise. Femurs were analyzed for bone mineral density and for bone mineral content by dual energy X-ray absorptiometry, biomechanical properties by three-point bending (Instron), and bone structure and formation by histomorphometry. Food intake did not differ among groups. Final body weights were significantly lower in Sw compared with Con (P < 0.05). Swimmers had significantly greater femoral shaft bone mineral density and content (P < 0.05) compared with Con. Femurs of the Sw group had greater mechanical properties (P < 0.05) compared with Con. Histomorphometric data were significantly better in the Sw group compared with Con after the 12-wk intervention (P < 0.05). In conclusion, data from this study demonstrate some beneficial effects of swim exercise on bone structure, turnover, and strength.

Perceived causes of urinary incontinence and reporting: a study with working women

The purposes of this study were to describe what working women perceived as the cause of their urinary incontinence (UI) and to determine if there was a relationship between identifying their UI cause and reporting it.

Order effects in the administration of a forced-choice procedure for detection of malingering in disability claimants' evaluations

100 disability claimants of the Social Security Administration referred for neuropsychological evaluation and 40 undergraduate college students asked to simulate brain damage were administered a measure for the detection of malingering, an abbreviated version of the Hiscock Forced-choice Procedure, and other neuropsychological tests. Half of each group was administered the Hiscock Procedure at the beginning of the battery; the other half was administered this test last. For both groups, the results indicated poorer performance on the earlier administration of the abbreviated Hiscock Forced-choice Procedure. Formal measures for detection of malingering should be an integral and early part of any neuropsychological evaluation in which the subject has a financial incentive to perform poorly.

Criterion-related validity and stability: equivalence of the MMPI and the MMPI-2

The differential criterion-related validity of the MMPI and MMPI-2 and their stability over a 4-month period of time were examined in a university population by correlating the clinical scales with their counterpart SCL-90-R factors. Fair to moderate correlations were found on all eight paired MMPI scales and SCL-90-R factors, while only two of eight MMPI-2/SCL-90-R pairings were found to be correlated significantly. Further analyses, however, found no significant differences between these MMPI/SCL-90-R and MMPI-2/SCL-90-R correlations. Adequate stability was found between MMPI-2 and SCL-90-R pairs over 4 months, except for the MMPI-2 D scale with the SCL-90-R Depression factor. Several issues related to the equivalency between the MMPI and the MMPI-2 were discussed.

Relative dissociation energy measurements using ion trap collisional activation

The measured minimum resonance excitation amplitudes for decomposition of polyatomic ions in the quadrupole ion trap collisional activation experiment are shown to correlate with literature critical energies. The present article describes how experiments can be performed to derive threshold resonance excitation amplitudes via the kinetics associated with collision-induced dissociation (i.e., dissociation rate constants) in the quadrupole ion trap. The relationship between these threshold values and critical energies is established empirically by using kinetic data acquired for molecular ions with critical energies measured with other techniques. The experiments are complicated by the change in optimum resonance excitation frequency with amplitude, due presumably to contributions from higher order fields. It is proposed that the threshold resonance excitation amplitude is a measure of the change in temperature of the parent ion population required to achieve a measurable rate of decomposition. The present results indicate that the quadrupole ion trap may see new applications as a quantitative tool for the study of gaseous ion chemistry.

Evidence of isomerization during ion isolation in the quadrupole ion trap

Evidence of ion isomerization during isolation in an ion trap mass spectrometer is presented. An ion-molecule reaction that is specific for the tolyl cation was used to monitor the relative abundance of this species. In particular, it has been observed that ion isolation in the ion trap can impart sufficient energy to the tolyl cation to cause it to isomerize to a form (presumably either the benzyl or the tropylium ion) that is not reactive with the neutral reagent. These results are important to consider in ion trap applications involving ion species having activation barriers for isomerization lower than the activation barriers for dissociation.

Reaction of analyte ions with neutral chemical ionization gas

Analytical Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA Ion-molecule reactions of neutral methane with analyte ions under normal methane chemical ionization conditions are discussed. Reactant ions can be generated by direct electron ionization (EI) fragmentation, chemical ionization (CI) fragmentation, or collision-induced dissociation (CID). Examples in which products of such reactions appear in mass spectra in both conventional CI sources in "beam" instruments and low pressure CI in a quadrupole ion trap are presented. Also shown is an example in which MS/MS product ions react with neutral methane used for CI in an ion trap. It is shown that it is relatively straightforward to recognize such reactions in a quadrupole ion trap and in certain cases to minimize or preclude them. Effects of various operating parameters have been investigated and are discussed.

Generation of substructure identification rules using feature-combinations from tandem mass spectra

Software to interpret tandem mass spectra, entitled Method for Analyzing Patterns in Spectra (MAPS), has been developed to provide substructure information for an automated compound identification system, This software consists of several program modules which manipulate databases of tandem mass spectra and substructure information, generate substructure identification rules, and apply these rules to the tandem mass spectra of unknown compounds to identify components of their structure. The MAPS rule generation program has been modified to generate rules based on specific combinations of spectral features that occur concertedly. False positives are drastically reduced by searching for "feature-combinations" that have 100% uniqueness with respect to a reference database of compounds. Recall is increased by the determination of multiple feature-combinations indicative of the presence of a given substructure. Strategies were developed in the algorithm for the discovery of feature-combinations that avoid the computation "explosion" that occurs when working with a large number of spectral features. The rules developed have the form: "IF feature-eombination a (FC a) or FC b,..., or FC x, THEN substructure SSn is present."

Evaluation of automatically generated substructure identification rules from tandem mass spectra

Substructure identification rules for phenothiazine and barbiturate substructures were generated by using a new version of the Method for Analyzing Patterns in Spectra (MAPS) software. This software uses tandem mass spectra and known substructure content of reference compounds to provide "feature-combination" rules. A feature-combination is a series of tandem mass spectral features which are completely unique to compounds containing a specified substructure. The current reference databases contain over 11,000 daughter spectra of 100 compounds acquired at two different collision gas pressures (i.e., single- and multiple-collision conditions). The results of rule evaluation procedures are presented and include a comparison of the spectral features developed in rule generation to those identified in documented fragmentation pathways of the indicated substructure. Two potential sources of error due to spectral feature and substructure "cross-correlation" were identified. If errors occur, they can be detected by calculating cross-correlation coefficients and edited from the rules. A beneficial cross-correlation involving feature-combinations was also discovered. The rules obtained by using single- and multiple-collision data were further evaluated by applying them to tandem mass spectra of 20 test compounds (compounds not in the reference database). The results of these evaluations give a good indication of the utility of the rules for use in an automated structure elucidation system for tandem mass spectrometry data.

Encopresis: behavioral parameters associated with children who fail medical management

The present study examined behavioral parameters such as parent management of encopresis and parental coping styles (active, cognitive, and avoidance) as predictors of success with medical management of encopresis. The results suggest that parents use a variety of management strategies and treatment success cannot be predicted using these variables. However, in line with previous research the presence of child behavior problems appeared to be a potential predictor variable.

Overt behavior of adolescent suicide attempters hospitalized on a general pediatrics floor

The usefulness of a direct observation assessment in evaluating adolescents hospitalized following a suicide attempt was investigated. Attempters hospitalized for medical stabilization were compared to adolescents hospitalized on the same pediatric floor by use of a modified version of the Hospitalized Adolescent Interaction Scale. Contrary to expectation, the adolescent suicide attempters did not differ significantly from medical patients regarding the activities they engaged in, interactions with others, out-of-bed behavior, or location on the floor. There were, however, significant differences between the two groups regarding affect, with the suicide attempters being rated as having more sullen facial expressions. A modest relationship was found between the self-report of depression and the activity level of the suicide attempters. These results are discussed in relation to behavior and depression during hospitalization and the role of behavior during hospitalization in disposition planning for adolescent suicide attempters.

The Hopelessness Scale for Children: psychometric properties with normal and emotionally disturbed adolescents

The psychometric properties of the Hopelessness Scale for Children (HSC) were evaluated with a sample of 834 normal adolescents and 93 adolescent suicide attempters. Factor analyses studies revealed two factors with both groups. Internal consistency with item-total score correlations were acceptable, while moderate test-retest reliability was found over a 10-week period with the normal sample. Support for the validity of the HSC was provided via studies with the suicide attempter group in which positive correlations with depression and depressive attributional style were found. Predicted differences between the suicide attempters, an outpatient psychiatric sample, and normal controls were also found. However, some items did not appear to discriminate suicide attempters from controls. Results are discussed in terms of the utility of the HSC with adolescents and adolescent suicide attempters and with regard to differences between child and adult samples in hopelessness.

Prevalence of bulimia in working and university women

The authors determined the prevalence of binge eating and bulimia in samples of 139 working women and 234 women who were university students. Although binge eating was found in 57 (41%) of the working women and 161 (69%) of the university women, the syndrome of bulimia was found in only two (1%) of the working women and 12 (5%) of the university women. These findings, although significant, stand in sharp contrast to popular reports that one-half or more of young women suffer from eating disorders. Further, they reveal systematic differences in the prevalence of bulimic behaviors between working women and university women. Results are discussed in terms of factors that might be associated with bulimia in these two samples of women.

Correlates of adult and child perceptions of social competency

In this study, the relationship between two commonly used measures of social competency, peer ratings of perceived status and adult ratings of assertiveness, were examined. In Phase I, high and low sociometric status children were videotaped responding to a series of role-play scenes; performance on these scenes was then rated retrospectively by adults for overall assertiveness. In Phase II, a second group of children who were unfamiliar with the videotaped children observed the taped scenes and provided ratings of likability, intelligence, working together, and attractiveness. In general, results revealed that children and adults differed in their ratings of the videotaped children. Further, boys used different cues in their ratings than did girls. More specifically, the sociometric status of girls was related to perceived attractiveness, whereas the sociometric status of boys was more closely related to perceived intelligence. Such findings suggest that children and adults look for and use different cues in their judgments. Given these differences, it is concluded that child and adult ratings should not be used interchangeably in the assessment of, and evaluation of, social competency in children.