What To Do (and Not to Do) with Causal Panel Analysis under Parallel Trends: Lessons from A Large Reanalysis Study

Two-way fixed effects (TWFE) models are ubiquitous in causal panel analysis in political science. However, recent methodological discussions challenge their validity in the presence of heterogeneous treatment effects (HTE) and violations of the parallel trends assumption (PTA). This burgeoning literature has introduced multiple estimators and diagnostics, leading to confusion among empirical researchers on two fronts: the reliability of existing results based on TWFE models and the current best practices. To address these concerns, we examined, replicated, and reanalyzed 37 articles from three leading political science journals that employed observational panel data with binary treatments. Using six newly introduced HTE-robust estimators, we find that although precision may be affected, the core conclusions derived from TWFE estimates largely remain unchanged. PTA violations and insufficient statistical power, however, continue to be significant obstacles to credible inferences. Based on these findings, we offer recommendations for improving practice in empirical research

Optimization Lactic Acid Production from Molasses Renewable Raw Material through Response Surface Methodology with Lactobacillus Casei M-15

AbstractLactic acid is one of the functional and valuable compounds utilized in food, pharmaceutical and chemical industries while Poly lactic acid (PLA) is a biodegradable polymer that has a variety of applications. In recent years, microbial conversion of renewable raw materials has become an important objective in industrial biotechnology. Sugarcane molasses can be considered as potential renewable raw materials in PLA production. The objective of this study is to optimized fermentation medium and conditions to obtain maximum lactic acid production and Colony Forming Unit (log CFU/mL) through response surface methodology (RSM). The maximum lactic acid production (38.33%) and log CFU/mL (8.30) by Lactobacillus casei M-15 was under 3.82% of molasses and 8.02% of inoculum level within 24 hr at 37°C respectively. This process will be advantageous for increasing yields of lactic acid and enhancing productivity by optimization technique. Moreover, it can reduce waste disposal and pollution and can selectively produce by sustainable agriculture such as agriculture material. In addition, the high-performance of lactic acid-producing microorganisms, qualified renewable raw materials and effective fermentation processes will be benefit for bioplastic technologies

Towards the Use of POP in a Global Coupled Navy Prediction System

LONG-TERM GOALS: Development of a global high resolution coupled atmosphere/ocean/ice model that assimilates data providing initial conditions from which forecasts are performed. Additionally, very high-resolution regional air/ocean coupled models will be nested into the global system at key strategic locations.Award Number: N0001401WR2015

Simulating the Storage and the Blockage Effects of Buildings in Urban Flood Modeling

Buildings often affect overland flow propagation in urban areas. Building walls change the direction and velocity of flow and can exclude interior spaces from flooding. However, water may intrude buildings when the flood level exceeds the height of protection. This study develops an inundation model that represents the resistance and the storage effects of buildings. This model was applied to central Taipei City, which is surrounded by the Danshui and Keelung Rivers. The inundation depth and extent were compared from models where the effects of buildings were included and excluded. Rainfall data from the Typhoon Nari event in 2001 was used in the simulation. The results showed that in the case where the effects of buildings were excluded inundation was underestimated in the metropolitan areas. Where the effects of buildings were considered in the model, the presented inundation model reproduces the inundation results more comparable with the observed flooding situation

Phase Identification of Smart Meters Using a Fourier Series Compression and a Statistical Clustering Algorithm

Accurate labeling of phase connectivity in electrical distribution systems is important for maintenance and operations but is often erroneous or missing. In this paper, we present a process to identify which smart meters must be in the same phase using a hierarchical clustering method on voltage time series data. Instead of working with the time series data directly, we apply the Fourier transform to represent the data in their frequency domain, remove $98\%$ of the Fourier coefficients, and use the remaining coefficients to cluster the meters are in the same phase. Result of this process is validated by confirming that cluster (phase) membership of meters does not change over two monthly periods. In addition, we also confirm that meters that belong to the same feeder within the distribution network are correctly classified into the same cluster, that is, assigned to the same phase.Comment: 5 pages, 6 figures, 4 table

Focus perception in Japanese: Effects of lexical accent and focus location.

This study explored the contexts in which native Japanese listeners have difficulty identifying prosodic focus. Using a 4AFC identification task, we compared native Japanese listeners' focus identification accuracy in different lexical accent × focus location conditions using resynthesised speech stimuli, which varied only in fundamental frequency. Experiment 1 compared the identification accuracy in lexical accent × focus location conditions using both natural and resynthesised stimuli. The results showed that focus identification rates were similar with the two stimulus types, thus establishing the reliability of the resynthesised stimuli. Experiment 2 explored these conditions further using only resynthesised stimuli. Narrow foci bearing the lexical pitch accent were always more correctly identified than unaccented ones, whereas the identification rate for final focus was the lowest among all focus locations. From these results, we argue that the difficulty of focus perception in Japanese is attributed to (i) the blocking of PFC by unaccented words, and (ii) similarity in F0 contours between lexical pitch accent and narrow focus, including in particular the similarity between downstep and PFC. Focus perception is therefore contingent on other concurrent communicative functions which may sometimes take precedence in a +PFC language

Which Matters Most? Perceptions of Family Income or Parental Education on Academic Achievement

The purpose of this study was to examine the impact of college students’ perception of family income, parental education levels, and race on academic achievement. Ninety-four second-year college students from a small, liberal arts, college in New York City responded to the survey during the Fall of 2009. Of the respondents, 52 were female and 42 were male. The survey collected demographic data on student perception of family income, parental education levels, and race. Academic achievement was measured by gathering students’ grade point averages. Findings in the research demonstrated that the education-level of the students’ fathers had the greatest impact on academic achievement

UKIDSS detections of cool brown dwarfs - proper motions of 14 known >>T5 dwarfs and discovery of three new T5.5-T6 dwarfs

AIMS: We contribute to improving the census of cool brown dwarfs (late-T and Y dwarfs) in the immediate solar neighbourhood. METHODS: By combining near-infrared (NIR) data of UKIDSS with mid-infrared WISE and other available NIR (2MASS) and red optical (SDSS $z$-band) multi-epoch data we detect high proper motion (HPM) objects with colours typical of late spectral types ($>$T5). We use NIR low-resolution spectroscopy for the classification of new candidates. RESULTS: We determined new proper motions for 14 known T5.5-Y0 dwarfs, many of them being significantly ($>$2-10 times) more accurate than previous ones. We detected three new candidates, ULAS J0954+0623, ULAS J1152+0359, and ULAS J1204-0150, by their HPMs and colours. Using previously published and new UKIDSS positions of the known nearby T8 dwarf WISE J0254+0223 we improved its trigonometric parallax to 165$\pm$20 mas. For the three new objects we obtained NIR spectroscopic follow-up with LBT/LUCIFER classifying them as T5.5 and T6 dwarfs. With their estimated spectroscopic distances of about 25-30 pc, their proper motions of about 430-650 mas/yr lead to tangential velocities of about 50-80 km/s typical of the Galactic thin disk population.Comment: 5 pages, 2 figures, plus 3 pages with 5 tables (online material), accepted for publication in Astronomy and Astrophysic

Which Matters Most? Perceptions of Family Income or Parental Education on Academic Achievement

The purpose of this study was to examine the impact of college students’ perception of family income, parental education levels, and race on academic achievement. Ninety-four second-year college students from a small, liberal arts, college in New York City responded to the survey during the Fall of 2009. Of the respondents, 52 were female and 42 were male. The survey collected demographic data on student perception of family income, parental education levels, and race. Academic achievement was measured by gathering students’ grade point averages. Findings in the research demonstrated that the education-level of the students’ fathers had the greatest impact on academic achievement