GROWING PAINS: AN HONORS THESIS OF CREATIVE WRITING

Most of the creative writing included in this thesis are nonfiction pieces; there are only a few that can be classified as fiction. They all connect to my own growth and development as a writer, and also as an individual struggling to find and establish my own identity. In the last four years I tried to make sense of my life and my struggles, especially my personal history of trauma. I can confidently say that I am in a much better place than I was when I first started my adventure at LC. Writing has been an important part of this adventure

Compositional uniformity, domain patterning and the mechanism underlying nano-chessboard arrays

We propose that systems exhibiting compositional patterning at the nanoscale, so far assumed to be due to some kind of ordered phase segregation, can be understood instead in terms of coherent, single phase ordering of minority motifs, caused by some constrained drive for uniformity. The essential features of this type of arrangements can be reproduced using a superspace construction typical of uniformity-driven orderings, which only requires the knowledge of the modulation vectors observed in the diffraction patterns. The idea is discussed in terms of a simple two dimensional lattice-gas model that simulates a binary system in which the dilution of the minority component is favored. This simple model already exhibits a hierarchy of arrangements similar to the experimentally observed nano-chessboard and nano-diamond patterns, which are described as occupational modulated structures with two independent modulation wave vectors and simple step-like occupation modulation functions.Comment: Preprint. 11 pages, 11 figure

Dynamic behaviour of multi-terminal VSC-based HVDC after a converter outage: DC control strategy

The aim of this paper is to evaluate the effect of DC-voltage control strategy on dynamic behaviour of multi-terminal Voltage-Source Converter (VSC)-Based HVDC after a converter outage. In this paper, two dc voltage control strategies are considered: (i) standard voltage margin method (SVMM) and (ii) standard voltage-droop method (SVDM). The impact is evaluated in this paper using time-domain simulations on simple test system using DIgSILENT PowerFactory considering a sudden disconnection of a converter-station. Simulation results demonstrate how important is the dc-voltage control strategy and the location/number of dc-buses involved in the dc-voltage on the dynamic response of the MTDC systems. The voltage margin control is capable to survive a converter outage just if this converter is operating on constant power mode

An X-ray study of the SNR G344.7-0.1 and the central object CXOU J170357.8-414302

Aims. We report results of an X-ray study of the supernova remnant (SNR) G344.7-0.1 and the point-like X-ray source located at the geometrical center of the SNR radio structure. Methods. The morphology and spectral properties of the remnant and the central X-ray point-like source were studied using data from the XMM-Newton and Chandra satellites. Archival radio data and infrared Spitzer observations at 8 and 24 $\mu$m were used to compare and study its multi-band properties at different wavelengths. Results. The XMM-Newton and Chandra observations reveal that the overall X-ray emission of G344.7-0.1 is extended and correlates very well with regions of bright radio and infrared emission. The X-ray spectrum is dominated by prominent atomic emission lines. These characteristics suggest that the X-ray emission originated in a thin thermal plasma, whose radiation is represented well by a plane-parallel shock plasma model (PSHOCK). Our study favors the scenario in which G344.7-0.1 is a 6 x 10^3 year old SNR expanding in a medium with a high density gradient and is most likely encountering a molecular cloud on the western side. In addition, we report the discovery of a soft point-like X-ray source located at the geometrical center of the radio SNR structure. The object presents some characteristics of the so-called compact central objects (CCO). However, its neutral hydrogen absorption column (N_{H}) is inconsistent with that of the SNR. Coincident with the position of the source, we found infrared and optical objects with typical early-K star characteristics. The X-ray source may be a foreground star or the CCO associated with the SNR. If this latter possibility were confirmed, the point-like source would be the farthest CCO detected so far and the eighth member of the new population of isolated and weakly magnetized neutron stars.Comment: 9 pages, 8 figures, accepted for publication in Astronomy and Astrophysics. Higher resolution figures can be seen on A&

Significance of calcium: its correlation with red and white muscle contraction, fatigue and potential

According to the predominant types of muscle fibers in an individual, they will have the ability to perform different types of exercises (both aerobic and anaerobic). To comprehend the mechanism of muscle fibers, which can act in diverse ways, enhancing either resistance or power, it is essential to examine the significance of calcium. Calcium plays a crucial role in both red and white muscle fibers. The release of calcium in white (fast-twitch) muscle fibers is significantly greater and faster, resulting in increased energy consumption, facilitating explosive physical activities. Conversely, in red (slow-twitch) muscle fibers, the release of calcium occurs in smaller amounts and over a prolonged period, leading to sustained energy consumption. The characteristics of contraction in red fibers enable endurance activities. A reduction in the amount of calcium results in diminished muscle contractile capacity, known as fatigue. The primary contributing factor, as previously mentioned, is the decline in calcium, but factors such as lactic acid and the dephosphorylation of the myosin head also contribute to its onset

α\alpha-cluster ANCs for nuclear astrophysics

Background. Many important $\alpha$-particle induced reactions for nuclear astrophysics may only be measured using indirect techniques due to small cross sections at the energy of interest. One of such indirect technique, is to determine the Asymptotic Normalization Coefficients (ANC) for near threshold resonances extracted from sub-Coulomb $\alpha$-transfer reactions. This approach provides a very valuable tool for studies of astrophysically important reaction rates since the results are practically model independent. However, the validity of the method has not been directly verified. Purpose. The aim of this letter is to verify the technique using the $^{16}$O($^6$Li,$d$)$^{20}$Ne reaction as a benchmark. The $^{20}$Ne nucleus has a well known $1^-$ state at excitation energy of 5.79 MeV with a width of 28 eV. Reproducing the known value with this technique is an ideal opportunity to verify the method. Method. The 1$^-$ state at 5.79 MeV is studied using the $\alpha$-transfer reaction $^{16}$O($^6$Li,$d$)$^{20}$Ne at sub-Coulomb energies. Results. The partial $\alpha$ width for the $1^-$ state at excitation energy of 5.79 MeV is extracted and compared with the known value, allowing the accuracy of the method to be evaluated. Conclusions. This study demonstrates that extracting the Asymptotic Normalization Coefficients using sub-Coulomb $\alpha$-transfer reactions is a powerful tool that can be used to determine the partial $\alpha$ width of near threshold states that may dominate astrophysically important nuclear reaction rates. \end{description

Pilot study of the characteristics of acute stroke events in patients discharged from the Carolina University Hospital, Puerto Rico in 2007

BACKGROUND: Stroke is the third leading cause of death in Puerto Rico. We examined the pre-hospital phase, management and case-fatality-rates (CFR) of patients discharged with acute stroke from the Carolina University of Puerto Rico Hospital during 2007. METHODS: Trained personnel collected information on demographics, delay-time, mode-of-transportation, management, and mortality from all medical records. STATAa was utilized to conduct univariate comparison of demographics, mode-of-transportation, therapeutics and diagnostic characteristics. Logistic regression analysis assessed cohort effect and controlled for confounders. RESULTS: The average age was 69.1 years, and 53% were males. The average delay between onset of symptoms suggestive of stroke and arrival at the emergency department was 4.5 hours. Only 62% of patients utilized Emergency Medical Services (EMS). Intravenous thrombolysis was not administered. Stroke mortality increased with age. Ischemic vs. hemorrhagic CFR was significantly higher (63.9% vs. 36.10%; p = 0.034). CONCLUSIONS: These findings highlight the potential benefit of evidence-based therapeutics and EMS use among stroke patients

Stellar 36,38^{36,38}Ar(n,γ)37,39(n,\gamma)^{37,39}Ar reactions and their effect on light neutron-rich nuclide synthesis

The $^{36}$Ar$(n,\gamma)^{37}$Ar ($t_{1/2}$ = 35 d) and $^{38}$Ar$(n,\gamma)^{39}$Ar (269 y) reactions were studied for the first time with a quasi-Maxwellian ($kT \sim 47$ keV) neutron flux for Maxwellian Average Cross Section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the $^{37}$Ar/$^{36}$Ar and $^{39}$Ar/$^{38}$Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The $^{37}$Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of $^{36}$Ar and $^{38}$Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) mb and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron capture cross sections of $^{36,38}$Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak $s$-process. The new production cross sections have implications also for the use of $^{37}$Ar and $^{39}$Ar as environmental tracers in the atmosphere and hydrosphere.Comment: 18 pages + Supp. Mat. (13 pages) Accepted for publication in Phys. Rev. Let

Probing the single-particle character of rotational states in 19^{19}F using a short-lived isomeric beam

A beam containing a substantial component of both the $J^{\pi}=5^+$, $T_{1/2}=162$ ns isomeric state of $^{18}$F and its $1^+$, 109.77-min ground state has been utilized to study members of the ground-state rotational band in $^{19}$F through the neutron transfer reaction $(d$,$p)$ in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2$^+$ band-terminating state. The agreement between shell-model calculations, using an interaction constructed within the $sd$ shell, and our experimental results reinforces the idea of a single-particle/collective duality in the descriptions of the structure of atomic nuclei