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X-ray diffractive imaging of controlled gas-phase molecules: Toward imaging of dynamics in the molecular frame
Get PDFWe report experimental results on the diffractive imaging of three-dimensionally aligned 2,5-diiodothiophene molecules. The molecules were aligned by chirped near-infrared laser pulses, and their structure was probed at a photon energy of 9.5 keV (λ ≈ 130 pm) provided by the Linac Coherent Light Source. Diffracted photons were recorded on the Cornell–SLAC pixel array detector, and a two-dimensional diffraction pattern of the equilibrium structure of 2,5-diiodothiophene was recorded. The retrieved distance between the two iodine atoms agrees with the quantum-chemically calculated molecular structure to be within 5%. The experimental approach allows for the imaging of intrinsic molecular dynamics in the molecular frame, albeit this requires more experimental data, which should be readily available at upcoming high-repetition-rate facilities
Robust control of the minima of high-order harmonics by fine-tuning the alignment of CO2 molecules for shaping attosecond pulses and probing molecular alignment
Get PDFIn a recent paper [C. Jin, S.-J. Wang, X. Zhao, S.-F. Zhao, and C. D. Lin, Phys. Rev. A 101, 013429 (2020)], we reported that the position and depth of the minima in the harmonic spectra of CO2 molecules can be dramatically manipulated by a slight change of the degree of alignment, thus providing a convenient method of shaping attosecond pulses which could lead to the splitting of a typical single attosecond burst into two. Here, we demonstrate that harmonic minima can also be dramatically controlled by changing the pump-probe angles to shape attosecond pulses. In the meanwhile, since the pump-probe angle-dependent harmonic spectra are very sensitive to the degree of alignment, harmonic spectra can also be used to calibrate the alignment distribution of molecules. We identify such robust control of harmonic generation is due to the optical property of CO2 and the coherent harmonic emission from the oriented molecules. The photoionization transition dipoles (PITDs) of CO2 exhibit deep minima that change rapidly with molecular orientations accompanied by large phase changes of π in PITDs, thus leading to strong interference when the dipoles are added up coherently
Children Victims of Parental Substance Abuse and Future Incarceration
Get PDFKirmser Undergraduate Research Award - Group category, honorable mentionJung Sim JunThe purpose of this mixed-method design study is to discover if the Adverse Childhood Experience(ACE) of having (a) parent(s) with a substance abuse issues effects the likelihood of the child being incarcerated in their future. In background research, we found that it is very common for abusive parents or other ACE to affect the child’s success, especially within their own future family violence and their presence in the criminal justice system. This study will survey approximately 100 inmates in the Topeka Correctional Facility and 100people in the Topeka, Kansas area who have never been incarcerated or arrested. The self-administered paper survey will ask questions about the individual’s parents are their parents use of substances when they were children and being incarcerates as an adult. The average score between the inmate group and the non-criminal group will be compared to see if there was a difference in their parent’s substance use severity in their childhoods.Finding these results is significant because it will show us a correlation between parental substance abuse and the link it has to their children’s future involvement in the criminal justice system (Correctional facilities).It also provides us with more specific information in relation to parental substance abuse and its effects on the child who falls victim and their future. If we find that this is a common issue and trend that parental substance abuse raises the likelihood of future incarceration for the child, we can also begin researching ways to combat this social issue
RPT101_2020_01
No full textThis informal report to the Kansas Legislature summarizes the impact of Kansas State's College of Agriculture educational programs in 2020
Students’ In-School Meal Experiences: A Study Of K - 5th Graders’ Level Of Satisfaction
Get PDFPURPOSE/OBJECTIVE
To explore the relationships between grade level and students’ in-school meal experiences including school food service outcome measures and satisfaction with food from home.
METHODS
Outcomes were measured using an online survey conducted within one urban school district. Food selection was self-reported while a 7-point emoji facial scale was used to measure students’ satisfaction with their dining experience, school foods, and food brought from home. A convenience sample of 1942 elementary students was solicited among kindergarten to 5th grade students in nine schools. Cluster analysis on mean responses was used to classify grades into like groups. Analysis of variance was used to determine differences in mean values for each item by grade group.
RESULTS
Results show that grade level had a significant impact on mean satisfaction ratings. Two distinct grade groups were identified: kindergarten through 2nd grades and 3rd through 5th grades. As grade level increased from kindergarten to 5th grade, students selected a wider variety of entrees but their ratings indicated decreased satisfaction. One striking exception was noted, satisfaction with food brought from home became more positive with increasing grade level.
APPLICATION TO CHILD NUTRITION PROFESSIONALS
Findings from this study highlight the importance of obtaining feedback as evenly as possible across grades in an effort to ensure collected data reflects the opinions of the whole population. If even sampling is not achieved, nutrition programs striving to gather information from their student body can apply grade-level weighting factors to compensate for over- or under-sampling. Findings from this study also suggest that there are opportunities to improve satisfaction and possibly increase program participation with solicitation of feedback. Understanding grade level differences in food item selection and satisfaction can provide valuable insights for food service professionals planning menus and making procurement decisions for their operations. Furthermore, results suggest a better understanding of the phenomena surrounding students’ satisfaction with food brought from home is needed
SRP1152
No full textCorn performance tests, conducted annually by the Kansas Agricultural Experiment Station, provide farmers, extension workers, and seed industry personnel with unbiased agronomic information on many of the corn hybrids marketed in the state. Because entry selection and location are voluntary, not all hybrids grown in the state are included in tests, and the same group of hybrids is not grown uniformly at all test locations
Electronic Population Transfer via Impulsive Stimulated X-Ray Raman Scattering with Attosecond Soft-X-Ray Pulses
Get PDFFree-electron lasers provide a source of x-ray pulses short enough and intense enough to drive nonlinearities in molecular systems. Impulsive interactions driven by these x-ray pulses provide a way to create and probe valence electron motions with high temporal and spatial resolution. Observing these electronic motions is crucial to understand the role of electronic coherence in chemical processes. A simple nonlinear technique for probing electronic motion, impulsive stimulated x-ray Raman scattering (ISXRS), involves a single impulsive interaction to produce a coherent superposition of electronic states. We demonstrate electronic population transfer via ISXRS using broad bandwidth (5.5 eV full width at half maximum) attosecond x-ray pulses produced by the Linac Coherent Light Source. The impulsive excitation is resonantly enhanced by the oxygen 1s→2π∗ resonance of nitric oxide (NO), and excited state neutral molecules are probed with a time-delayed UV laser pulse
Experimental study of laser-induced isomerization dynamics of specific C2H2q ions
Get PDFWe investigate intense, ultrafast laser-induced isomerization and two-body fragmentation of acetylene monocations and dications using coincidence three-dimensional momentum imaging. Whereas the vast majority of previous work on strong-field isomerization and fragmentation of acetylene has necessarily involved ionization, by focusing solely on dissociation of ion-beam targets, we ensure that the dynamics ensue within a single molecular ion species, potentially simplifying interpretation. We demonstrate the rich information that can be extracted from such a measurement and discuss advantages and disadvantages of this approach
The Opportunity Cost of the Conservation Reserve Program: A Kansas Land Example
Get PDFThe effects of the Conservation Reserve Program (CRP) on farmland values is investigated using a set of parcel-level data for land sales in Kansas over the period 1998 to 2014. The sales data are used to estimate a hedonic model of land values that allows for the opportunity cost of CRP enrollment to vary across space and time. Factors impacting the opportunity costs include the relative productivity of land, returns to farming, and the time remaining under the CRP contracts. We find that the discount associated with having land under CRP contract averages 7%
Smooth periodic gauge satisfying crystal symmetry and periodicity to study high-harmonic generation in solids
Get PDFIntense lasers can easily drive nonadiabatic transitions of excited electron wave packets across the Brillouin zones, thus transition dipole moments (TDM) between energy bands of solids should be continuous, satisfying crystal symmetry, and periodic at zone boundaries. While current ab initio algorithms are powerful in calculating band structures of solids, they all introduced random phases into the eigenfunctions at each crystal momentum k . Here we show how to choose a “smooth-periodic” gauge where TDMs can be smooth versus k , preserving crystal symmetry, as well as maintaining periodic at boundaries. The symmetry properties of TDMs with respect to k ensure the absence of even-order harmonics from MgO with inversion symmetry, while the TDM in the “smooth-periodic” gauge for broken-symmetry ZnO is responsible for even harmonics that were underestimated in previous simulations. These results reveal the importance of correctly treating the complex TDMs that satisfy crystal symmetry and continuous across zone boundaries in nonlinear laser-solid interactions, which has been elusive in most theories so far