Linear Stability of Solitary Waves for the Isothermal Euler-Poisson System

We study the asymptotic linear stability of a two-parameter family of solitary waves for the isothermal Euler-Poisson system. When the linearized equations about the solitary waves are considered, the associated eigenvalue problem in L-2 space has a zero eigenvalue embedded in the neutral spectrum, i.e., there is no spectral gap. To resolve this issue, use is made of an exponentially weighted L-2 norm so that the essential spectrum is strictly shifted into the left-half plane, and this is closely related to the fact that solitary waves exist in the super-ion-sonic regime. Furthermore, in a certain long-wavelength scaling, we show that the Evans function for the Euler-Poisson system converges to that for the Korteweg-de Vries (KdV) equation as an amplitude parameter tends to zero, from which we deduce that the origin is the only eigenvalue on its natural domain with algebraic multiplicity two. We also show that the solitary waves are spectrally stable in L-2 space. Moreover, we discuss (in)stability of large amplitude solitary waves

ENInst: Enhancing Weakly-supervised Low-shot Instance Segmentation

We address a weakly-supervised low-shot instance segmentation, an annotation-efficient training method to deal with novel classes effectively. Since it is an under-explored problem, we first investigate the difficulty of the problem and identify the performance bottleneck by conducting systematic analyses of model components and individual sub-tasks with a simple baseline model. Based on the analyses, we propose ENInst with sub-task enhancement methods: instance-wise mask refinement for enhancing pixel localization quality and novel classifier composition for improving classification accuracy. Our proposed method lifts the overall performance by enhancing the performance of each sub-task. We demonstrate that our ENInst is 7.5 times more efficient in achieving comparable performance to the existing fully-supervised few-shot models and even outperforms them at times.Comment: Accepted at Pattern Recognition (PR

A case of gangliocytic paraganglioma in the ampulla of Vater

<p>Abstract</p> <p>Background</p> <p>Duodenal gangliocytic paraganglioma is an extremely rare tumor and few cases have been reported to date.</p> <p>Case presentation</p> <p>The authors report a case of gangliocytic paraganglioma verified by post-op pathology after pancreaticoduodenectomy for a tumor in the ampulla of Vater. The 56-year-old male patient concerned visited our emergency room with melena that started one week prior to hospitalization. The patient was diagnosed to have a tumor in the ampulla of Vater with bleeding on its surface. However post-op, he was diagnosed as having gangliocytic paraganglioma by immunohistochemistry.</p> <p>Conclusion</p> <p>This tumor has precise clinical implications, and if continuous follow up is conducted after careful diagnosis and surgical treatment, invasive major operations, such as, radical pancreaticoduodenectomy can be avoided.</p

Overexpression of p53, Mutation of hMLH1 and Microsatellite Instability in Gastric Carcinomas: Clinicopathologic Implications and Prognosis

Purpose: Mutated p53 is a tumor suppressor gene, hMLH1 is a mismatch repair gene, and hypermethylation of hMLH1 follows microsatellite instability (MSI). This research`s aim is to investigate mutated p53, inactivated hMLH1 and MSI in gastric cancer and their clinicopathologic implications. Methods: Between 2003 and 2007, 618 patients underwent curative radical gastrectomy for gastric cancer at Seoul National University Bundang Hospital in Korea. We reviewed their medical charts and the pathologic reports with immunohistochemistry for p53, hMLH1 and polymerase chain reaction for MSI in 509, 499, and 561 cases, respectively. These genetic markers were statistically compared with clinicopathologic features and postoperative survival. Results: The expression ratios of mutated p53, inactivated hMLH1, and MSI were 32.8%, 8.4%, and 8.7%, respectively. Mutation of p53 occurred more frequently in aged group (over 40), differentiated group (against the non-differentiated group), intestinal type, infiltrative type and positive lymph node metastasis group. Inactivated hMLH1 occurred more frequently in aged group, differentiated group, intestinal type and expanding growth type group. MSI was found more frequently in aged group, intestinal type and expanding growth type group. All three genetic markers had no significant associations with the 5-year survival. Conclusion: We identified significant relationships between mutated p53, inactivated hMLH1, and MSI with some clinicopathologic features of gastric cancer. However, there were no apparent relationships between p53, hMLH1, and MSI and prognosis.KU KB, 2007, J KOREAN SURG SOC, V72, P283WOERNER SM, 2006, CANCER BIOMARK, V2, P69LIU P, 2005, WORLD J GASTROENTERO, V11, P4904Lee HS, 2002, MODERN PATHOL, V15, P632Nakajima T, 2001, INT J CANCER, V94, P208Samowitz WS, 2001, AM J PATHOL, V158, P1517Rugge M, 2000, J CLIN PATHOL-MOL PA, V53, P207Wu MS, 2000, GENE CHROMOSOME CANC, V27, P403OH SH, 2000, J KOREAN SURG SOC, V59, P206Fleisher AS, 1999, CANCER RES, V59, P1090Leung SY, 1999, CANCER RES, V59, P159Monig SP, 1997, DIGEST DIS SCI, V42, P2463Thibodeau SN, 1996, CANCER RES, V56, P4836Starzynska T, 1996, CANCER, V77, P2005DosSantos NR, 1996, GASTROENTEROLOGY, V110, P38Peddanna N, 1995, ANTICANCER RES, V15, P2055TAMURA G, 1995, CANCER RES, V55, P1933SERUCA R, 1995, INT J CANCER, V64, P32CORREA P, 1994, CANCER RES, V54, pS1941BODMER W, 1994, NAT GENET, V6, P217RHYU MG, 1994, ONCOGENE, V9, P29UCHINO S, 1993, INT J CANCER, V54, P759TAHARA E, 1993, J CANCER RES CLIN, V119, P265CORREA P, 1992, CANCER RES, V52, P6735MARTIN HM, 1992, INT J CANCER, V50, P859HOLLSTEIN MC, 1991, CANCER RES, V51, P4102YONISHROUACH E, 1991, NATURE, V352, P345HARRIS AL, 1990, J PATHOL, V162, P5

The Status of Protein Supply to Patients in the Trauma and Surgical Intensive Care Units and the Effects of Feedback on Protein Supply: A Multicenter Study

Purpose To investigate the status of protein supply by comparing the recommended amount with the delivered amount of protein in patients in the trauma and surgical intensive care units (ICU). Feedback on the protein supply status was presented to each hospital, and we evaluated whether the protein supply had increased to an appropriate level. Methods In this retrospective observational multicenter study, nutritional information on patients in the trauma and surgical ICUs who had received nutritional support intervention was collected on the 1st Wednesday of each month at two-month intervals from August 2020 to June 2021, from nine domestic hospitals in Korea. Every two months, the nutritional status of each hospital was shared with all hospitals, and each nutritional support team received feedback on protein supply status. Results There were 246 patients from nine hospitals included in this study, and data over the study period from six protein days, were analyzed. The mean ratios of delivered calories to calculated required calories were 74.0%, 80.8%, 85.4%, 77.9%, 71.3%, and 82.1% on Protein Days 1, 2, 3, 4, 5, and 6, respectively. The mean ratios of delivered protein to calculated required protein were 73.0%, 77.2%, 78.9%, 79.3%, 69.4%, and 89.6% on Protein Days 1, 2, 3, 4, 5, and 6, respectively. Conclusion Protein supply increased to an appropriate level, feedback on protein supply status may have increased the protein supply ratio and promoted appropriate protein supply and nutritional support for patients in the trauma and surgical ICUs

ION DYNAMICS OF THE EULER-POISSON SYSTEM (Mathematical Analysis in Fluid and Gas Dynamics)

We consider the Euler-Poisson system with Boltzmann relation that is a fundamental fluid model describing the dynamics of ions in an electrostatic plasma. It is often employed to study phenomena of plasma such as plasma sheaths and double layers. We show that the Euler-Poisson system admits a two-parameter family of solitary waves in the super-ion-sonic regime, and prove their the convective linear stability. We also propose a criterion for the singularity formation of the pressureless case, under which we prove that the smooth solutions develop a C¹ blow-up in a finite time and obtain their temporal blow-up rates. Our blow-up condition does not require the largeness of gradient of velocity

Small amplitude limit of solitary waves for the Euler-Poisson system

The one-dimensional Euler-Poisson system arises in the study of phenomena of plasma such as plasma solitons, plasma sheaths, and double layers. When the system is rescaled by the Gardner-Morikawa transformation, the rescaled system is known to be formally approximated by the Korteweg-de Vries (KdV) equation. In light of this, we show existence of solitary wave solutions of the Euler-Poisson system in the stretched moving frame given by the transformation, and prove that they converge to the solitary wave solution of the associated KdV equation as the small amplitude parameter tends to zero. Our results assert that the formal expansion for the rescaled system is mathematically valid in the presence of solitary waves and justify Sagdeev&apos;s formal approximation for the solitary wave solutions of the pressureless Euler-Poisson system. Our work extends to the isothermal case

Reconstruction of the initial state from the data measured on a sphere for plasma-acoustic wave equations

We establish a reconstruction formula for the initial information of a density (pressure) from the time records of data measured on a sphere for a certain class of wave-type equations. We first derive a reconstruction formula of integral form, and by applying the theory of Fourier Bessel series for this, we also obtain a formula of discrete version, which is more robust and numerically advantageous in the presence of noises. The reconstruction formulas we propose in this work are explicit and applicable to a wider class of wave-type equations including the plasma-acoustic wave equations

National Assessment of Opportunities for Improvement in Preventable Trauma Deaths: A Mixed-Methods Study

Trauma is a significant public health issue worldwide, particularly affecting economically active age groups. Quality management of trauma care at the national level is crucial to improve outcomes of major trauma. In Korea, a biennial nationwide survey on preventable trauma death rate is conducted. Based on the survey results, we analyzed opportunities for improving the trauma treatment process. Expert panels reviewed records of 8282 and 8482 trauma-related deaths in 2017 and 2019, respectively, identifying 258 and 160 cases in each year as preventable deaths. Opportunities for improvement were categorized into prehospital, interhospital, and hospital stages. Hemorrhage was the primary cause of death, followed by sepsis/multiorgan failure and central nervous system injury. Delayed hemostatic procedures and transfusions were common areas for improvement in hospital stage. Interhospital transfers experienced significant delays in arrival time. This study emphasizes the need to enhance trauma care by refining treatment techniques, centralizing patients in specialized facilities, and implementing comprehensive reviews and performance improvements throughout the patient transfer system. The findings offer valuable insights for addressing trauma care improvement from both clinical and systemic perspectives

Evaluation of the Potential for Improvement of Clinical Outcomes in Trauma Patients with Massive Hemorrhage by Maintaining a High Plasma-to-Red Blood Cell Ratio during the First Hour of Hospitalization

Several reports indicate that early plasma transfusion may promote survival and reduce the incidence of traumatic coagulopathy in situations of massive bleeding. Consequently, it is recommended to maintain a plasma and RBC transfusion ratio between 1 : 1 and 1 : 2 at the start of admission. This retrospective study examined the effect of an early high plasma : RBC ratio on mortality rates by adopting a massive transfusion protocol (MTP) that forced an early and rapid issue of plasma products. Patients who received massive transfusions at a single trauma center between January 2014 and May 2020 were included in the study. A new protocol was established in January 2020, wherein a fixed amount of plasma was issued following MTP activation. Patients who underwent massive transfusions before and after the adoption of the new protocol were compared. In total, 1059 patients met the inclusion criteria. Fifty-one patients who underwent MTP were propensity score-matched with the patients who received a nonprotocolized massive transfusion. The MTP group had a higher plasma : RBC ratio at 1 h (0.8 vs. 0.2) and 4 h of hospitalization (1.1 vs. 0.6), with no significant between-group difference in the plasma : RBC ratio at 24 h of hospitalization. The MTP group had a lower 24 h mortality rate than the control group. There was no significant difference in the 30-day mortality. Using MTP to achieve a high plasma : RBC ratio in the early period of hospitalization appeared to affect 24-hour mortality; however, 30-day mortality did not change