225 research outputs found
WIC Participation and Breastfeeding After the 2009 WIC Revision: A Propensity Score Approach
In this study, we examined the association between participation in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) and breastfeeding outcomes before and after the 2009 revisions. Four-thousand-three-hundred-and-eight WIC-eligible children younger than 60 months were included from the 2005-2014 National Health and Nutrition Examination Survey (NHANES). We compared two birth cohorts with regard to their associations between WIC participation and being ever-breastfed and breastfed at 6 months. We estimated the average effect of the treatment for the treated to assess the causal effect of WIC participation on breastfeeding based on propensity score matching. The results showed that WIC-eligible participating children born between 2000 and 2008 were significantly less likely than WIC-eligible nonparticipating children to ever receive breastfeeding (p \u3c 0.05) or to be breastfed at 6 months (p \u3c 0.05). Among children born between 2009 and 2014, WIC-eligible participating children were no longer less likely to ever receive breastfeeding compared to WIC-eligible nonparticipating children; the gap remained in breastfeeding at 6-months (p \u3c 0.05). The disparities in prevalence of ever breastfed between WIC-eligible participants and nonparticipants have been eliminated since the 2009 WIC revision. More efforts are needed to improve breastfeeding persistence among WIC-participating mother-infant dyads
Minimizing the Maximum Flow Time in the Online Food Delivery Problem
We study a common delivery problem encountered in nowadays online food-ordering platforms: Customers order dishes online, and the restaurant delivers the food after receiving the order. Specifically, we study a problem where k vehicles of capacity c are serving a set of requests ordering food from one restaurant. After a request arrives, it can be served by a vehicle moving from the restaurant to its delivery location. We are interested in serving all requests while minimizing the maximum flow-time, i.e., the maximum time length a customer waits to receive his/her food after submitting the order.
We show that the problem is hard in both offline and online settings even when k = 1 and c = ?: There is a hardness of approximation of ?(n) for the offline problem, and a lower bound of ?(n) on the competitive ratio of any online algorithm, where n is number of points in the metric.
We circumvent the strong negative results in two directions. Our main result is an O(1)-competitive online algorithm for the uncapacitated (i.e, c = ?) food delivery problem on tree metrics; we also have negative result showing that the condition c = ? is needed. Then we explore the speed-augmentation model where our online algorithm is allowed to use vehicles with faster speed. We show that a moderate speeding factor leads to a constant competitive ratio, and we prove a tight trade-off between the speeding factor and the competitive ratio
Prenatal Perception of WIC Breastfeeding Recommendation Predicts Breastfeeding Outcomes in Infant\u27s First Year
Objectives
Promoting breastfeeding (BF) is a priority of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Prior research found that pregnant mothers who believed WIC recommends BF only (versus BF and formula equally OK) were more likely to initiate BF and continue through 1 month postpartum. We examine whether such mothers are more likely to continue to exclusively BF through 5 months and BF at all through the infant\u27s first year. Methods
Data are from the WIC Infant and Toddler Feeding Practices Study-2 (ITFPS-2), a longitudinal study that includes 2,649 mothers who completed prenatal interviews. Four BF outcomes were examined: (a) exclusive BF through 5 months, (b) any BF through 11 months, (c) age of the infant (in days up to 7 months) when formula is initiated, and (d) age of the infant (days up to 13 months) when mother stopped BF. We examined the associations of prenatal belief that WIC recommended BF only (yes/no) with each BF outcome using the Cox regression model to estimate the likelihood of breastfeeding outcomes over time while controlling for prenatal infant feeding intention (IFI) and socio-demographic factors. All analyses accounted for complex survey design effects. Results
Of the pregnant mothers, 41% perceived that WIC recommends BF only; 59% perceived that WIC recommends BF and formula equally. Mothers who perceived WIC to recommend BF only were less likely to initiate formula by 7 months than those who perceived WIC recommended BF and formula equally [Hazard Ratio (HR) = 0.84; P \u3c 0.05], after controlling for IFI.WIC perception was a significant predictor only when IFI was not controlled for the other three BF outcomes: stopped exclusive BF through 5 months (HR = 0.83; P \u3c 0.05), stopped any BF through 11 months (HR = 0.80; P \u3c 0.01), and stopped any BF by 13 months (HR = 0.82; P \u3c 0.01). Conclusions
Perception of WIC BF recommendation can be a significant predictor of BF outcomes in the infant\u27s first year, possibly by affecting BF intention. Funding Sources
ITFPS-2 is funded by the Food and Nutrition Service, U.S. Department of Agriculture (USDA). Support for the study analysis was provided by the Economic Research Service, USDA CRA 58–4000-8–0038-R. Findings and conclusions are those of the authors and should not be construed to represent any official USDA or US Government determination or policy
Multiple Factors Drive Variation of Forest Root Biomass in Southwestern China
The roots linking the above-ground organs and soil are key components for estimating net primary productivity and carbon sequestration of forests. The patterns and drivers of root biomass in forest have not been examined well at the regional scale, especially for the widely distributed forest ecosystems in southwestern China. We attempted to determine the spatial patterns of root biomass (RB, Mg/ha), annual increment root biomass (AIRB, Mg/ha/year), ratio of root and above-ground (RRA), and the relative contributions of abiotic and biotic factors that drive the variation of root biomass. Forest biomass and multiple factors (climate, soil, forest types, and stand characteristics) of 318 plots in this region (790,000 km2) were analyzed in this research. The AB (the mean values for forest aboveground biomass per ha, Mg/ha), RB, AIRB, and RRA were 126 Mg/ha, 28 Mg/ha, 0.69 Mg/ha and 0.22, respectively. AB, RB, AIRB, and RRA varied across all the plots and forest types. Both RB and AIRB showed significant spatial patterns of distribution, while RRA did not show any spatial patterns of distribution. Up to 28.4% of variation in total of RB, AIRB, and RRA can be attributed to the climate, soil, and stand characteristics. The explained or contribution rates of climate, soil, and stand characteristics for variation of whole forest root biomass were 6.7%, 16.9%, and 10.9%, respectively. Path analysis in structural equation model (SEM) indicated the direct influence of stand age on RB. AIRB was greater than that of the other factors. Climate, soil and stand characteristics in different forest types could explain 9.7%–96.1%, 15.4%–96.4%, and 36.7%–99.4% of variations in RB, AIRB, and RRA, respectively, which suggests that the multiple factors may be important in explaining the variations in forest root biomass. The results of the analysis of root biomass per ha, annual increment of root biomass per ha, and ratio of root and above-ground in the seven forest types categorized by climate, soil, and stand characteristics may be used for accurately determining C sequestration by the forest root and estimating forest biomass in this region
A 4-channel 12-bit high-voltage radiation-hardened digital-to-analog converter for low orbit satellite applications
This paper presents a circuit design and an implementation of a four-channel 12-bit digital-to-analog converter (DAC) with high-voltage operation and radiation-tolerant attribute using a specific CSMC H8312 0.5-μm Bi-CMOS technology to achieve the functionality across a wide-temperature range from -55 °C to 125 °C. In this paper, an R-2R resistor network is adopted in the DAC to provide necessary resistors matching which improves the DAC precision and linearity with both the global common centroid and local common centroid layout. Therefore, no additional, complicated digital calibration or laser-trimming are needed in this design. The experimental and measurement results show that the maximum frequency of the single-chip four-channel 12-bit R-2R ladder high-voltage radiation-tolerant DAC is 100 kHz, and the designed DAC achieves the maximum value of differential non-linearity of 0.18 LSB, and the maximum value of integral non-linearity of -0.53 LSB at 125 °C, which is close to the optimal DAC performance. The performance of the proposed DAC keeps constant over the whole temperature range from -55 °C to 125 °C. Furthermore, an enhanced radiation-hardened design has been demonstrated by utilizing a radiation chamber experimental setup. The fabricated radiation-tolerant DAC chipset occupies a die area of 7 mm x 7 mm in total including pads (core active area of 4 mm x 5 mm excluding pads) and consumes less than 525 mW, output voltage ranges from -10 to +10 V
Modified Dachengqi Tang improves decreased gastrointestinal motility in postoperative esophageal cancer patients
AbstractObjectiveTo investigate the clinical effects of modified Dachengqi Tang (DCQT) on promoting gastrointestinal motility in post-operative esophageal cancer patients.MethodsSixty postoperative esophageal cancer patients were enrolled and randomly assigned to the modified treatment group or the control group (30 patients in each group). Patients in the treatment group were given DCQT made from decocted herbs and administered via nasojejunal tube at a dosage of 150 mL. Gastrointestinal motility was assessed by recording time for recovery of bowel sounds, flatus, defecation, and the total amount of gastric drainage during the first three postoperative days. Plasma motilin (MTL) and vasoactive intestinal peptide (VIP) were measured one hour before and three days after surgery.ResultsCompared with the control group, the times to first bowel sound, flatus, and defecation were significantly shorter and there was less gastric drainage in the treatment group (P < 0.01, P < 0.01, P < 0.01, and P < 0.05, respectively). In the treatment group, postoperative plasma MTL was significantly higher (P < 0.01) and VIP was significantly lower than those in the control group (P < 0.05). There was no difference found in either MTL or VIP from before to after operation in the treatment group (P > 0.05). MTL was significantly lower and VIP was higher postoperatively in the control group, compared to before surgery (P < 0.01).ConclusionsModified DCQT effectively improved decreased gastrointestinal motility in postoperative esophageal cancer patients by increasing MTL and reducing VIP
A novel multi-dimensional reliability approach for floating wind turbines under power production conditions
Floating offshore wind turbines (FOWT) generate green renewable energy and are a vital part of the modern offshore wind energy industry. Robust predicting extreme offshore loads during FOWT operations is an important safety concern. Excessive structural bending moments may occur during certain sea conditions, posing an operational risk of structural damage. This paper uses the FAST code to analyze offshore wind turbine structural loads due to environmental loads acting on a specific FOWT under actual local environmental conditions. The work proposes a unique Gaidai-Fu-Xing structural reliability approach that is probably best suited for multi-dimensional structural responses that have been simulated or measured over a long period to produce relatively large ergodic time series. In the context of numerical simulation, unlike existing reliability approaches, the novel methodology does not need to re-start simulation again each time the system fails. As shown in this work, an accurate forecast of the probability of system failure can be made using measured structural response. Furthermore, traditional reliability techniques cannot effectively deal with large dimensionality systems and cross-correction across multiple dimensions. The paper aims to establish a state-of-the-art method for extracting essential information concerning extreme responses of the FOWT through simulated time-history data. Three key components of structural loads are analyzed, including the blade-root out-of-plane bending moment, tower fore-aft bending moment, and mooring line tension. The approach suggested in this study allows predicting failure probability efficiently for a non-linear multi-dimensional dynamic system as a whole.publishedVersio
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