instruction:
In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
question:
Context: Poultry remains a major source of foodborne bacterial infections. A variety of additives with presumed anti-microbial and/or growth-promoting effects are commonly added to poultry feed during commercial grow-out, yet the effects of these additives on the gastrointestinal microbial community (the GI microbiome) as the bird matures remain largely unknown. Here we compared temporal changes in the cecal microbiome to the effects of formic acid, propionic acid, and medium-chain fatty acids (MCFA) added to feed and/or drinking water.', 'Cecal bacterial communities at day of hatch (n\u2009=\u20095 birds), 7d (n\u2009=\u200932), 21d (n\u2009=\u200927), and 42d (n\u2009=\u200936) post-hatch were surveyed using direct 454 sequencing of 16S rRNA gene amplicons from each bird in combination with cultivation-based recovery of a Salmonella Typhimurium marker strain and quantitative-PCR targeting Clostridium perfringens. Treatment effects on specific pathogens were generally non-significant. S. Typhimurium introduced by oral gavage at day of hatch was recovered by cultivation from nearly all birds sampled across treatments at 7d and 21d, but by 42d, S. Typhimurium was only recovered from ca. 25% of birds, regardless of treatment. Sequencing data also revealed non-significant treatment effects on genera containing known pathogens and on the cecal microbiome as a whole. In contrast, temporal changes in the cecal microbiome were dramatic, highly significant, and consistent across treatments. At 7d, the cecal community was dominated by three genera (Flavonifractor, Pseudoflavonifractor, and a Lachnospiracea sequence type) that accounted for more than half of sequences. By 21d post-hatch, a single genus (Faecalibacterium) accounted for 23-55% of sequences, and the number of Clostridium 16S rRNA gene copies detected by quantitative-PCR reached a maximum.\Question: Are successional changes in the chicken cecal microbiome during 42 days of growth independent of organic acid feed additives?
answer:
Over the 42 d experiment, the cecal bacterial community changed significantly as measured by a variety of ecological metrics and increases in the complexity of co-occurrence networks. Management of poultry to improve animal health, nutrition, or food safety may need to consider the interactive effects of any treatments with the dramatic temporal shifts in the taxonomic composition of the cecal microbiome as described here.


question:
Context: To assess how different imputation methods used to account for missing variance data in primary studies influence tests of heterogeneity and pooled results from a meta-analysis with continuous outcomes.', 'Point and variance estimates for changes in serum creatinine, glomerular filtration rate, systolic blood pressure, and diastolic blood pressure were variably reported among 48 primary longitudinal studies of living kidney donors (71%-78% of point estimates were reported, 8%-13% of variance data were reported). We compared the results of meta-analysis, which either were restricted to available data or used four methods to impute missing variance data. These methods used reported P-values, reported nonparametric summaries, results from other similar studies using multiple imputation, or results from estimated correlation coefficients.', 'Significant heterogeneity was present in all four outcomes regardless of the imputation methods applied. The random effects point estimates and 95% confidence intervals varied little across imputation methods, and the differences were not clinically significant.\Question: Do imputing variance estimates alter the conclusions of a meta-analysis with continuous outcomes : a case study of changes in renal function after living kidney donation?
answer:
Different methods to impute the variance data in the primary studies did not alter the conclusions from this meta-analysis of continuous outcomes. Such reproducibility increases confidence in the results. However, as with most meta-analyses, there was no gold standard of truth, and results must be interpreted judiciously. The generalization of these findings to other meta-analyses, which differ in outcomes, missing data, or between-study heterogeneity, requires further consideration.


question:
Context: To define whether laparoscopic gastric banding or laparoscopic Roux-en-Y gastric bypass represents the better approach to treat patients with morbid obesity.', 'Two techniques, laparoscopic gastric bypass or gastric banding, are currently widely used to treat morbid obesity. Since both procedures offer certain advantages, a strong controversy exists as to which operation should be proposed to these patients. Therefore, data are urgently needed to identify the best therapy.', 'Since randomized trials are most likely not feasible because of the highly different invasiveness and irreversibility of these procedures, a matched-pair design of a large prospectively collected database appears to be the best method. Therefore, we used our prospective database including 678 bariatric procedures performed at our institution since 1995. A total of 103 consecutive patients with laparoscopic gastric bypass were randomly matched to 103 patients with laparoscopic gastric banding according to age, body mass index, and gender.', 'Both groups were comparable regarding age, gender, body mass index, excessive weight, fat mass, and comorbidites such as diabetes, heart disease, and hypertension. Feasibility and safety: All gastric banding procedures were performed laparoscopically, and one gastric bypass operation had to be converted to an open procedure. Mean operating time was 145 minutes for gastric banding and 190 minutes for gastric bypass (P < 0.001). Hospital stay was 3.3 days for gastric banding and 8.4 days for gastric bypass. The incidence of early postoperative complications was not significantly different, but late complications were significantly more frequent in the gastric banding group (pouch dilatation). There was no mortality in both groups. Efficiency: Body mass index decreased from 48.0 to 36.8 kg/m in the gastric banding group and from 47.8 to 31.9 kg/m in the gastric bypass group within 2 years of surgery. These differences became significant from the first postoperative month until the end of the follow-up (24 months). The gastric bypass procedure achieved a significantly better reduction of comorbidities.\Question: Is laparoscopic gastric bypass superior to laparoscopic gastric banding for treatment of morbid obesity?
answer:

Laparoscopic gastric banding and laparoscopic gastric bypass are feasible and safe. Pouch dilatations after gastric banding are responsible for more late complications compared with the gastric bypass. Laparoscopic gastric bypass offers a significant advantage regarding weight loss and reduction of comorbidities after surgery. Therefore, in our hands, laparoscopic Roux-en-Y gastric bypass appears to be the therapy of choice.