Quasiclassical analysis of Bloch oscillations in non-Hermitian tight-binding lattices

Many features of Bloch oscillations in one-dimensional quantum lattices with a static force can be described by quasiclassical considerations for example by means of the acceleration theorem, at least for Hermitian systems. Here the quasiclassical approach is extended to non-Hermitian lattices, which are of increasing interest. The analysis is based on a generalised non-Hermitian phase space dynamics developed recently. Applications to a single-band tight-binding system demonstrate that many features of the quantum dynamics can be understood from this classical description qualitatively and even quantitatively. Two non-Hermitian and $PT$-symmetric examples are studied, a Hatano-Nelson lattice with real coupling constants and a system with purely imaginary couplings, both for initially localised states in space or in momentum. It is shown that the time-evolution of the norm of the wave packet and the expectation values of position and momentum can be described in a classical picture.Comment: 20 pages, 8 figures, typos corrected, slightly extended, accepted for publication in New Journal of Physics in Focus Issue on Parity-Time Symmetry in Optics and Photonic

Differentiation of Cardiac from Noncardiac Pleural Effusions in Cats using Second-Generation Quantitative and Point-of-Care NT-proBNP Measurements

BACKGROUND: Pleural effusion is a common cause of dyspnea in cats. N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) measurement, using a first‐generation quantitative ELISA, in plasma and pleural fluid differentiates cardiac from noncardiac causes of pleural effusion. HYPOTHESIS/OBJECTIVES: To determine whether NT‐proBNP measurements using second‐generation quantitative ELISA and point‐of‐care (POC) tests in plasma and pleural fluid distinguish cardiac from noncardiac pleural effusions and how results compare to the first‐generation ELISA. ANIMALS: Thirty‐eight cats (US cohort) and 40 cats (UK cohort) presenting with cardiogenic or noncardiogenic pleural effusion. METHODS: Prospective cohort study. Twenty‐one and 17 cats in the US cohort, and 22 and 18 cats in the UK cohort were classified as having cardiac or noncardiac pleural effusion, respectively. NT‐proBNP concentrations in paired plasma and pleural fluid samples were measured using second‐generation ELISA and POC assays. RESULTS: The second‐generation ELISA differentiated cardiac from noncardiac pleural effusion with good diagnostic accuracy (plasma: sensitivity, 95.2%, specificity, 82.4%; pleural fluid: sensitivity, 100%, specificity, 76.5%). NT‐proBNP concentrations were greater in pleural fluid (719 pmol/L (134–1500)) than plasma (678 pmol/L (61–1500), P = 0.003), resulting in different cut‐off values depending on the sample type. The POC test had good sensitivity (95.2%) and specificity (87.5%) when using plasma samples. In pleural fluid samples, the POC test had good sensitivity (100%) but low specificity (64.7%). Diagnostic accuracy was similar between first‐ and second‐generation ELISA assays. CONCLUSIONS AND CLINICAL IMPORTANCE: Measurement of NT‐proBNP using a quantitative ELISA in plasma and pleural fluid or POC test in plasma, but not pleural fluid, distinguishes cardiac from noncardiac causes of pleural effusion in cats

Clinical vignette: Tension pneumothorax complicating septic pulmonary emboli

Case Presentation: A 40 year old female was referred from the local jail with a tension pneumothorax. She had a long history of intravenous (IV) heroin and cocaine use followed by a 2-year history of sobriety. She had resumed intravenous heroin use 3 weeks before admission and soon thereafter developed fever and chills. She was incarcerated 7 days before admission. Five days before admission she developed progressive dyspnea and left-sided pleuritic chest pain. On arrival in the emergency department, she was found to be febrile (39.0 deg C), tachycardic (121 beats/min), tachypneic (34 breaths/min), and hypoxemic. Leukocyte count was 12,100 cells/mcL. A chest x-ray showed a large left tension pneumothorax with mediastinal shift and a moderate left sided pleural effusion. After placement of a left-sided chest tube, computerized tomography revealed multifocal peripheral cavitary nodules suggestive of septic emboli. Per the radiology report, the etiology of the pneumothorax was compatible with bronchopleural fistula, suspected to be due to a peripheral cavitary nodule in the anteromedial left lower lobe. A transthoracic echocardiogram revealed a large tricuspid valve vegetation measuring 0.95 x 1.47cm. Blood cultures grew methicillin-sensitive Staphylococcus aureus. She was treated with nafcillin. Her initial hospital course included respiratory failure requiring mechanical ventilation and development of a right-sided pneumothorax requiring placement of an additional chest tube. Serial chest x-rays showed improvement of the cavitary lesions and resolution of the bilateral pneumothoraces. She was eventually transferred to a skilled nursing facility to complete a six week course of nafcillin. At the time of discharge, she was without leukocytosis and no longer required supplemental oxygen. Discussion: Pnemothorax is an uncommon complication of pneumonia; it may be seen with Pneumocystis jiroveci, tuberculosis, or necrotizing bacterial pneumonia. Pneumothorax associated with septic pulmonary emboli is a very rare complication of Staphyloccus aureus bacteremia. The pathophysiology is presumed to be erosion of a embolic bacterial cavitary lesion into a bronchus with creation of a bronchopulmonary fistula. Conclusions: Septic pulmonary embolus is a severe complication of staphylococcal bacteremia and right-sided endocarditis that may be seen in IV drug users. On rare occasion, it may be associated with pneumothorax. This infection is often associated with prolonged morbidity and increased mortalit

Abnormal Grain Growth in S-816 Alloy

From Introduction: "This report presents the results obtained to date of an investigation to establish the fundamental causes of abnormal growth in S-816 alloy under conditions encountered during the forging of blades for the gas turbine of jet engines.

Teaching Tip: Socio-Cultural Learning to Increase Student Engagement in Introduction to MIS

Introduction to Management Information Systems (MIS) is a challenging course to teach because of the broad expanse of rapidly-changing material, the centrality of the course to the business curriculum, students’ demand for interactive teaching rather than traditional lecture, and general student disinterest in or lack of familiarity with the subject. Further compounding these problems, faculty may not be adequately comfortable with or trained in active teaching modalities. To address these challenges, we used principles of socio-cultural learning to design a system of class activities to teach the dynamic concepts commonly found in the Introduction to MIS course. Faculty can adapt and customize this system to suit almost any teaching style without significant preparation. Capitalizing on students’ own experiences, we provide ad hoc activities that encourage students to work outside their comfort zone, to communicate and challenge material, to value their own expertise, and to gain confidence working independently. This paper specifically answers the call for more research explaining the “how” of teaching rather than the “what” and will prove useful and immediately actionable for novice and seasoned faculty alike

Socio-Cultural Learning to Increase Student Engagement in Introduction to MIS

Introduction to Management Information Systems (MIS) is a challenging course to teach because of the broad expanse of rapidlychanging material, the centrality of the course to the business curriculum, students’ demand for interactive teaching rather than traditional lecture, and general student disinterest in or lack of familiarity with the subject. Further compounding these problems, faculty may not be adequately comfortable with or trained in active teaching modalities. To address these challenges, we used principles of socio-cultural learning to design a system of class activities to teach the dynamic concepts commonly found in the Introduction to MIS course. Faculty can adapt and customize this system to suit almost any teaching style without significant preparation. Capitalizing on students’ own experiences, we provide ad hoc activities that encourage students to work outside their comfort zone, to communicate and challenge material, to value their own expertise, and to gain confidence working independently. This paper specifically answers the call for more research explaining the “how” of teaching rather than the “what” and will prove useful and immediately actionable for novice and seasoned faculty alike

Addressing Gaps in Nursing Home Emergency Preparedness

Background: Previous studies have identified significant gaps in nursing home emergency preparedness. Few of these studies have specifically surveyed nursing homes about activities that would be helpful in improving preparedness. Methods: In 2012, we mailed to 134 nursing homes in West Texas and New Mexico a survey about the facility, facility preparedness, and types of assistance would be helpful in improving preparedness for their facility. We performed standard statistical analysis on returned surveys and compared facilities in rural communities to those in urban communities. Results: 37/134 (28%) of facilities returned the survey. 21/36 (65%) of surveys were from facilities in rural communities. All facilities had a written all-hazards emergency preparedness plan. 34/36 (95%) included an evacuation plan and 32/37 (86%) included a shelter in place plan. 23/36 (65%) had updated their plan in the past year. Only 12/36 (33%) of facilities had participated in a disaster exercise in the previous 2 years. More than 50% of plans lacked specific guidance about mortuary services, information about building construction, written agreements with transportation companies, a process to rapidly credential volunteers, and prepared educational material. Overall, facilities reported intermediate confidence that their response plan reflected their facilitys ability to respond effectively to a disaster. In the previous 5 years, 16/37 (27%) of facilities had experienced an emergency (prolonged power outage, severe disease outbreak, or gun violence). Though 23/37 (62%) of facilities considered emergency management agencies to be major partners, 13/35 (37%) reported no previous assistance from these agencies. Facilities desired the following items to improve their facility\u27s emergency preparedness: staff training (68%), collaboration during an exercise (68%), and critique of their response plan (62%). There were no statistical differences between facilities in urban and rural communities with regard to the perceived confidence in the plan, plan deficiencies, or desire for assistance in improving emergency preparedness of their facility. Conclusions: This small survey found no difference between rural and urban nursing homes with regard to emergency preparedness, and identified specific activities that could improve nursing home emergency preparedness.\u2

Validation and preliminary data from a health-related quality of life questionnaire for owners of dogs with cardiac disease

BACKGROUND: Cardiac disease in dogs impacts the quality of life (QoL) of their owners, but owners\u27 QoL has not been comprehensively assessed in this population. OBJECTIVES: To develop, validate, and provide preliminary data from a health-related QoL (hrQoL) questionnaire for owners of dogs with cardiac disease. SUBJECTS: A total of 141 owners of dogs with cardiac disease were studied. METHODS: An owner hrQoL (O-hrQoL) questionnaire containing 20 items related to areas of a person\u27s life that could be impacted by caring for a dog with cardiac disease was developed and administered to owners of dogs with cardiac disease. The highest possible total score was 100, with higher scores indicating a worse hrQoL. Readability, internal consistency, face and construct validity, and item-total correlations were assessed. RESULTS: Median O-hrQoL score was 35 (range, 0-87). The questionnaire had good internal consistency (Cronbach\u27s alpha = 0.933), construct validity (Spearman\u27s r = 0.38-0.53; Kendall\u27s tau = 0.30-0.43; P \u3c .001), and item-total correlation (Spearman\u27s r = 0.44-0.79; Kendall\u27s tau = 0.34-0.66; all P \u3c .001). Fifty percent of owners indicated a negative effect of dogs\u27 cardiac disease on their own QoL, but all owners responded that caring for their dogs either had strengthened (n = 76; 53.9%) or had no effect on their relationship with their dog (n = 65; 46.1%). CONCLUSIONS AND CLINICAL IMPORTANCE: The O-hrQoL questionnaire had good validity, and results suggest that owners\u27 QoL is significantly impacted by caring for dogs with cardiac disease. Additional research on effective approaches to minimizing the negative effects of a dog\u27s cardiac disease on the owner is warranted

Double-Crested Cormorant Colony Effects on Soil Chemistry, Vegetation Structure and Avian Diversity in a Southeastern Reservoir System

Ornithogenic material delivered by Double-crested Cormorants (Phalacrocorax auritus) from their nesting colonies have been documented to effect vegetation, soil chemistry and tree and plant health in the northern breeding grounds of Canada and the United States (U.S.). However, little work has been done on impacts to avian communities or in temperate forest ecosystems. We compared soil chemistry, vegetation and tree structure and diversity and effects on avian communities among colony islands, uninhabited islands and abandoned colony islands within Guntersville Reservoir, a temperate forest ecosystem. Concentrations of potassium (K), phosphorus (P) and nitrate (NO3-) in soil were negatively related to cormorant use, while tree diversity was lower on historic (tree mean = 4.35 ± 2.46 species) and colony (tree mean = 3.91 ± 3.12 species) islands relative to control islands (tree mean = 9.11 ± 3.88 species). Canopy cover was less (min: \u3c 20%), and midstories denser on colony and historic islands relative to control islands. Avian diversity was lower for colony islands (mean = 6 ± 3 species) than both control (11 ± 7 species) and historic (10 ± 7 species) islands. These effects of cormorant nesting can be seen even after 10 years of colony abandonment supporting that cormorants can have long-term effects on insular habitats even in temperate forest ecosystems