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.

The influence of grass silage-to-maize silage ratio and concentrate composition on methane emissions, performance and milk composition of dairy cows.

It is well-established that altering the proportion of starch and fibre in ruminant diets can alter ruminal and post-ruminal digestion, although quantitative evidence that this reduces enteric methane (CH4) production in dairy cattle is lacking. The objective of this study was to examine the effect of varying grass-to-maize silage ratio (70 : 30 and 30 : 70 DM basis), offered ad libitum, with either a concentrate that was high in starch or fibre, on CH4 production, intake, performance and milk composition of dairy cows. A total of 20 cows were allocated to one of the four experimental diets in a two-by-two factorial design run as a Latin square with each period lasting 28 days. Measurements were conducted during the final 7 days of each period. Cows offered the high maize silage ration had a higher dry matter intake (DMI), milk yield, milk energy output and lower CH4 emissions when expressed per kg DMI and per unit of ingested gross energy, but there was no difference in total CH4 production. Several of the milk long-chain fatty acids (FA) were affected by forage treatment with the most notable being an increase in 18:0, 18:1 c9, 18:2 c9 c12 and total mono unsaturated FA, observed in cows offered the higher inclusion of maize silage, and an increase in 18:3 c9 c12 c15 when offered the higher grass silage ration. Varying the composition of the concentrate had no effect on DMI or milk production; however, when the high-starch concentrate was fed, milk protein concentration and milk FAs, 10:0, 14:1, 15:0, 16:1, increased and 18:0 decreased. Interactions were observed for milk fat concentration, being lower in cows offered high-grass silage and high-fibre concentrates compared with the high-starch concentrate, and FA 17:0, which was the highest in milk from cows fed the high-grass silage diet supplemented with the high-starch concentrate. In conclusion, increasing the proportion of maize silage in the diets of dairy cows increased intake and performance, and reduced CH4 production, but only when expressed on a DM or energy intake basis, whereas starch-to-fibre ratio in the concentrate had little effect on performance or CH4 production.

Effect of inorganic or organic copper fed without or with added sulfur and molybdenum on the performance, indicators of copper status, and hepatic mRNA in dairy cows.

The effect of inorganic (INORG) or organic (ORG) Cu, fed without (-) or with (+) additional S and Mo on Cu status and performance was examined using 56 early lactation dairy cows in a 2×2 factorial study design. Supplementary Cu was added as either CuSO4 or BioplexCu (Alltech Inc., Nicholasville, KY) to provide an additional 10mg of Cu/kg of dry matter (DM), with S added at 1.5g/kg of DM and Mo at 6.8mg/kg of DM to reduce Cu bioavailability. The basal ration was composed of corn and grass silages (2:1 respectively, DM basis) and straight feeds. Cows commenced the study at wk 7 of lactation and remained on treatment for 16 wk. An interaction existed between Cu source and added S and Mo on DM intake, with cows offered INORG- Cu having an increased intake compared with those offered INORG+ or ORG- Cu. Milk yield averaged 35.4kg/d, and was 5% higher with milk fat content 6% lower in cows fed INORG compared with ORG Cu, but milk fat yield, energy-corrected milk yield, and milk protein content did not differ between treatments. A trend existed for cows to have a higher body weight gain when offered ORG compared with INORG Cu. Cows fed diets containing INORG Cu had a higher milk concentration of C17:0 and C18:3n-3 compared with those fed diets containing ORG Cu. Cows fed added S and Mo had a lower milk concentration of C17:0 and C18:0 compared with those that were not supplemented. No effect was observed of dietary treatment on plasma Cu concentration, which averaged 13.1 µmol/L, except during wk 12 when cows receiving added S and Mo had a lower concentration. No effect was observed of Cu source on mean plasma Mo concentrations, but during wk 16 cows offered INORG Cu had a higher concentration than those offered ORG Cu. Hepatic Cu levels decreased by approximately 0.9mg/kg of DM per day when fed additional S and Mo, but no effect of Cu source was observed. A trend existed for hepatic ATPase, Cu++ transporting, beta polypeptide (ATP7B) to be upregulated in cows when fed S and Mo along with ORG but not INORG Cu. In conclusion, the inclusion of an ORG compared with an INORG source of Cu reduced milk yield but increased milk fat concentration and body weight gain, with no effect on energy-corrected milk yield. Little effect was observed of dietary Cu supply on plasma mineral concentration, liver mRNA abundance, or milk fatty acid profile, whereas the addition of S and Mo reduced hepatic Cu concentrations.

Effect of whole-crop pea (Pisum sativum L.) silages differing in condensed tannin content as a substitute for grass silage and soybean meal on the performance, metabolism, and carcass characteristics of lambs.

Two experiments were conducted to investigate the effect of inclusion of whole-crop pea (WCP) silages, differing in condensed tannin content, as a substitute for grass silage (GS) and soybean meal on lamb metabolism, performance, plasma metabolites, digestibility, and carcass characteristics. In both experiments lambs were offered either solely GS or a 50:50 mix on a DM basis of GS with either low-tannin (LTPS) or high-tannin (HTPS) pea silage ad libitum. Each forage mix was fed with either 400 g/d of low-protein (LP) concentrate or 400 g/d of LP with an additional 200 g/d of pelletized soybean meal (HP), resulting in 6 dietary treatments. Experiment 1 examined the effects of the diets on metabolism, digestibility, and N balance using 6 lambs in 4 periods of 21 d in an incomplete crossover design. Experiment 2 used 48 lambs and examined the effects of the diets on ADG, plasma metabolites, and carcass characteristics over 56 d. Both experiments were analyzed using a 3 × 2 factorial arrangement of treatments. In Exp. 1, lambs offered the LTPS diets had a greater (P < 0.05) digestibility of DM and OM than those offered the GS diets. Lambs offered the WCP silages had an increased (P < 0.05) N intake, N output, and digestibility of GE compared with those offered GS. Mean N digestibility was greatest (P < 0.05) in lambs offered LTPS. Lambs offered HP diets had increased (P < 0.001) digestibility of DM, OM, GE and N, and N- intake, output, retention, and digestibility compared with those offered the LP diets. In Exp. 2, there was no effect (P > 0.05) of forage type on intake, slaughter BW, or feed conversion efficiency (FCE). However, lambs offered the LTPS had a greater (P < 0.05) ADG than those offered the GS diets. Feeding diets containing HP increased (P < 0.001) total DMI, slaughter BW, ADG, and FCE. Lambs offered the WCP had a greater (P < 0.05) plasma ß-hydroxybutyrate and urea concentration compared with those offered the GS diets. Feeding lambs HP diets increased (P < 0.05) plasma urea and total protein. Forage mix had no effect (P > 0.05) on carcass composition except for fat depth, which was greater (P < 0.05) in lambs offered WCP silage. Diets containing the HP increased (P < 0.05) carcass weight, hind leg circumference, chop dimensions, and kidney weight. It was concluded that lambs offered LTPS performed better than those offered GS and that LTPS has a concentrate sparing effect. Additionally, the increased tannin concentration in HTPS did not increase performance over lambs offered either GS or LTPS.

Methane emissions, feed intake, performance, digestibility, and rumen fermentation of finishing beef cattle offered whole-crop wheat silages differing in grain content.

This study aimed to quantify the methane emissions and feed intake, performance, carcass traits, digestibility, and rumen fermentation characteristics of finishing beef cattle offered diets based on whole-crop wheat (WCW) silages differing in grain content and to rank these relative to diets based on grass silage (GS) and ad libitum concentrates (ALC). In Exp. 1, a total of 90 continental crossbred steers [538 +/- 27.6 kg of BW (mean +/- SD)] were blocked by BW and assigned in a randomized complete block design to 1 of 6 treatments based on 4 WCW silages [grain-to-straw plus chaff ratios of 11:89 (WCW I), 21:79 (WCW II), 31:69 (WCW III), and 47:53 (WCW IV)], GS, and ALC. Increasing grain content in WCW silage resulted in a quadratic (P = 0.01) response in DMI, with a linear (P < 0.001) increase in carcass gain [CG; 577 (WCW I), 650 (WCW II), 765 (WCW III), and 757 g/d (WCW IV)]. The G:F also increased linearly (P < 0.001) in response to increasing the grain content of WCW silage. A quadratic (P < 0.01) response in daily methane output [295 (WCW I), 315 (WCW II), 322 (WCW III), and 273 g/d (WCW IV)], measured using the sulfur hexafluoride tracer technique, was observed in response to increasing the grain content of WCW; however, linear decreases were observed when expressed relative to DMI (P = 0.01) and CG (P < 0.001). Cattle offered GS exhibited carcass gains similar to those offered WCW silage diets and had greater methane emissions than cattle in any other treatment when expressed relative to DMI. Cattle offered ALC exhibited greater (P < 0.01) carcass gains and decreased (P < 0.001) methane emissions, irrespective of the unit of expression, compared with cattle in any of the silage-based treatments. In Exp. 2, rumen fermentation parameters were determined using 4 ruminally cannulated Rotbunde-Holstein steers (413 +/- 30.1 kg of BW) randomly allocated among WCW I, the average of WCW II and III (WCW II/III), WCW IV, and GS in a 4 x 4 Latin square design. Ruminal pH and total VFA concentration did not differ across dietary treatments. Molar proportion of acetic acid decreased (P = 0.01), with propionic acid tending to increase (P = 0.06) with increasing grain content. It was concluded that increasing the grain content of WCW silage reduced methane emissions relative to DMI and CG and improved animal performance. However, the relativity of GS to WCW in terms of methane emissions was dependent on the unit of expression used. Cattle offered ALC exhibited decreased methane emissions and greater performance than those offered any of the silage-based treatments.

Methane emissions, feed intake, and performance of finishing beef cattle offered maize silages harvested at 4 different stages of maturity.

This experiment aimed to quantify the methane emissions and intake, digestibility, performance, and carcass characteristics of finishing beef cattle offered maize (Zea mays) silages harvested at 1 of 4 sequential stages of maturity and to relate these values to those obtained from animals offered an ad libitum concentrate-based diet. Sixty continental crossbred steers with a mean initial BW of 531 kg (SD 23.8) were blocked (n = 12 blocks) according to BW and allocated from within block to 1 of 5 dietary treatments in a randomized complete block design: maize silage harvested on September 13 (DM = 277 g/kg), maize silage harvested on September 28 (DM = 315 g/kg), maize silage harvested on October 9 (DM = 339 g/kg), maize silage harvested on October 23 (DM = 333 g/kg), and ad libitum concentrates (ALC). Diets based on maize silage were supplemented with 2.57 kg of concentrate DM daily, and ALC diets were supplemented with 1.27 kg of grass silage DM daily. Silage and total DMI were greater (P = 0.004) with maize silage harvested on September 28 than with any other treatment, which in turn did not differ. Advancing maize maturity at harvest did not affect BW or carcass gain, with the ALC diet exhibiting greater (P = 0.036) rates of carcass gain than any of the maize silage-based treatments. Apparent in vivo digestibility, determined using the AIA indigestible marker technique, was not affected by harvest maturity, with no linear or quadratic trends being identified. Digestibility of DM from the ALC diet was greater (P < 0.001) than with any of the maize silage treatments. Starch digestibility did not differ across maize silage maturities; however, a linear (P = 0.009) decrease in NDF digestibility was observed. Methane emissions, (g/d) measured using the sulfur hexafluoride tracer technique, were not affected by maize silage maturity. Methane emissions relative to DMI tended (P = 0.05) to decline with advancing maize silage maturity, with a similar decline observed when methane was expressed per kilogram of carcass gain. Advancing maize maturity did not result in significant linear or quadratic responses in methane output proportional to GE intake. The ALC diet resulted in less methane output than the maize silage treatments irrespective of the unit of expression. In conclusion, advancing maize harvest maturity did not affect beef cattle performance but reduced methane output relative to DMI and carcass gain. Cattle offered ALC exhibited greater rates of BW gain and less emission of methane compared with cattle offered any of the maize silage treatments.

Effect of sward dry matter digestibility on methane production, ruminal fermentation, and microbial populations of zero-grazed beef cattle.

Increasing the digestibility of pasture for grazing ruminants has been proposed as a low-cost practical means of reducing ruminant CH(4) emissions. At high feed intake levels, the proportion of energy lost as CH(4) decreases as the digestibility of the diet increases. Therefore, improving forage digestibility may improve productivity as DM and energy intake are increased. A zero-grazing experiment was conducted to determine the effect of sward DM digestibility (DMD) on DMI, CH(4) emissions, and indices of rumen fermentation of beef animals. Twelve Charolais-cross heifers were assigned to 1 of 2 treatments, with 6 heifers per dietary treatment. Additionally, 4 cannulated Aberdeen Angus-cross steers were randomly allocated to each of these 2 treatments in a crossover design. Dietary treatments consisted of swards managed to produce (i) high digestibility pasture (high DMD) or (ii) pasture with less digestibility (low DMD), both offered for ad libitum intake. All animals were zero-grazed and offered freshly cut herbage twice daily. In vitro DMD values for the high and low DMD swards were 816 and 706 g/kg of DM. Heifers offered the high DMD grass had greater (P < 0.001) daily DMI of 7.66 kg compared with 5.38 kg for those offered the low DMD grass. Heifers offered the high DMD grass had greater (P = 0.003) daily CH(4) production (193 g of CH(4)/d) than those offered the low DMD grass (138 g of CH(4)/d). However, when corrected for DMI, digestible DMI, or ingested gross energy, there was no difference (P > 0.05) in CH(4) production between dietary treatments. For cannulated steers, intake tended (P = 0.06) to be greater for the high DMD grass (5.56 vs. 4.27 kg of DM/d), but rumen protozoa (4.95 x 10(4)/mL; P = 0.62); rumen ammonia (34 mg of N/L; P = 0.24); rumen total VFA (103 mM; P = 0.58), and rumen pH (6.8; P = 0.43) did not differ between treatments. There was no difference in total bacteria numbers, relative expression of the mcrA gene, and numbers of cycles to threshold for fungi when determined using quantitative PCR between dietary treatments with mean values of 73.0 ng/microL, 0.958, and 21.75 C(T), respectively. Results of this study demonstrate that there was no difference in CH(4) production when corrected for intake or rumen fermentation variables of beef cattle offered a high or low digestibility sward.

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.

How bad is civil commitment? A study of attitudes toward violence and involuntary hospitalization.

Civil commitment statutes throughout the nation authorize involuntary hospitalization for persons who are believed dangerous to others, even though clinicians' ability to predict violence is imperfect. Decision-makers faced with ambiguous evidence about future violence must make either-or decisions about involuntary hospitalization. Such decisions can be characterized as "true positives" (hospitalization of a person who would have acted violently if released), "true negatives" (nonviolent person is not hospitalized), "false positive" (nonviolent person is hospitalized), or "false negative" (person is released and subsequently acts violently). This paper presents two pilot studies of attitudes about false negative and false positive decisions, and explains how Decision Theory can use information gleaned from such studies to establish optimal decision thresholds for initiating involuntary hospitalization. Subjects expressed a broad range of implicit tolerances for false negative and false positive predictions. Though most subjects preferred being hospitalized for three days to being the victim of a knife-wielding attacker, a substantial minority preferred being attacked to being hospitalized. The article briefly explores the practical implications of these findings, which include an implicit endorsement of stringent commitment policies that would release a large fraction of potentially violent persons.

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.

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.

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.

Optimization of automatically generated rules for predicting the presence and absence of substructures from MS and MS/MS data.

A pattern-recognition/artificial-intelligence program, referred to as MAPS (Method for Analyzing Patterns in Spectra), was recently developed to identify the relationships that exist between substructures and the characteristic features they produce in the spectra from mass spectrometry (MS) and successive mass spectrometry (MS/MS). MAPS has been extended to utilize these relationships to formulate exclusion rules as well as inclusion rules, so that the absence of recognized substructures can be predicted as well as their presence. The potential usefulness of each MS and MS/MS spectral feature in such rule formulation is characterized by correlation and uniqueness factors. The correlation factor expresses the degree of correlation between a feature and a specific substructure; the uniqueness factor expresses the uniqueness of a feature with respect to that substructure. Features with high correlation factors are most use for predicting the absence of substructures, whereas features with high uniqueness factors are most useful for predicting their presence. Feature intensity-data have been found to improve the inclusion-rule performance and degrade the exclusion-rule performance. Criteria for optimizing the predictive abilities of both rule types are discussed.