Capacitance Measurements of Defects in Solar Cells: Checking the Model Assumptions

Capacitance measurements of solar cells are able to detect minute changes in charge in the material. For that reason, capacitance is used in many methods to electrically characterize defects in the solar cell. Standard interpretations of capacitance rely on many assumptions, which, if wrong can skew the results. We explore possible alternate explanations for capacitance transitions, which may not be linked directly to defects, such as a non-ideal back contact, and series resistance

Role of Contacts in Capacitance Measurements of Solar Cells

The electronic properties of low cost, thin-film solar cells are complicated by the non-ideal nature of the semiconductor layers. Typically, the fundamental electronic properties of such materials are evaluated using current-voltage and capacitance-voltage measurements. However, in these devices, it is common for the back contact to be non-ohmic. We are exploring the impact of such a back contact on the outcome of standard capacitance-based characterization techniques. We compare computer models of capacitance response with measurements of simple model electronic circuits and of solar cell devices

Capacitance Measurements of Defects in Solar Cells: Checking the Model Assumptions

Capacitance measurements of solar cells are sensitive to minute changes in charge in the material. For that reason, capacitance is used in several methods to electrically characterize defects in the solar cell. Standard interpretations of capacitance rely on many assumptions, which, if wrong can skew the results. We explore possible alternative explanations for capacitance transitions, such as a non-ideal back contact and series resistance. Using Drive Level Capacitance Profiling measurements, a capacitance step is linked to a defect between the energy bands of a solar cell

FIRST RECORD OF AN ADULT MALE EVENING BAT FROM KANSAS

The evening bat (Nycticeius humeralis) occurs throughout the eastern and southeastern United States and into extreme northeastern Mexico, approximately 42° to 18° N latitude (Watkins and Shump 1981). Although records of females are common, records of adult male evening bats are rare in the northern portion of the species range (Watkins 1969, Watkins 1972). Jones et al. (1967) suggested that adult males might not accompany females to at least some parts of the parturient range. As part of a larger study (Davis 2003) we surveyed bats on Fort Leavenworth Military Reservation (FLMR), Leavenworth County, Kansas in July 2002 and June and July 2003. Bats were captured by using mist netting, for a total effort of 48 net nights over two summers. Universal Transverse Mercator (UTM) coordinates were recorded for all collecting locations and are available from authors. We captured II evening bats, including three specimens now deposited in the Collection of Recent Mammals, Midwestern State University (MWSU). Ten of the evening bats captured in our study included three adult females and seven juveniles. All of these individuals were captured in openings of the cottonwood-sycamore (Populus deltoides~Platanus occidentalis) and pecan-sugarberry (Carya illinoensis-Celtis laevigata) floodplain forests along the Missouri River. The other individual (MWSU 22086) represents the first record of an adult male evening bat for Kansas (Jones et al. 1967, Sparks and Choate 2000). The adult male was captured in oak-hickory (Quercus alba-Carya ovata) upland forest; northing 0334200, easting 4358631

An Integrated Approach to Learning Communities: Designing for Place-Based, Communication-Intensive Learning

This article describes the design of a learning community that paired an English Composition and a Public Speaking course at the New York City College of Technology (City Tech) and explains the embedded teaching strategies: flexible scheduling, integrated assignments, and a place-based (Brooklyn) focus. These tactics, developed with the aim of engaging first-semester students in their general-education communication courses, served to orient students to City Tech and its neighboring environment. Flexible scheduling helped avoid making concessions due to time constraints and allowed for greater fairness and efficiency, while also expanding opportunities for classroom and out-of-classroom activities. Designing overlapping assignments helped students by scaffolding coursework throughout the semester, building toward increasingly challenging course objectives. The place-based focus on Brooklyn oriented students to the campus, supported their ability to find nearby places that expanded their campus experience, and gave them tools for interacting critically with their surroundings. Grounded in maker pedagogy, the semester’s final project asked students to make a shared Google Map that included their videos and summaries of their research, creating a virtual tour of downtown Brooklyn. Ultimately, these strategies supported better student success and engagement in the courses while providing a creative outlet for successful college work. Jody R. Rosen is an Assistant Professor of English and Co-Director of the OpenLab at New York City College of Technology, CUNY, where she teaches in the First-Year Learning Community program each fall semester. Her scholarship focuses on pedagogical approaches to foster community, and on Modernist narratological representations of gender and sexuality. M. Justin Davis is a Postdoctoral Fellow in the Department of Communication Studies at Northeastern University. His research explores processes related to the production, performance, and consumption of identity, cultural memory, and public mind

Coupled Cluster Externally Corrected by Adaptive Configuration Interaction

An externally corrected coupled cluster (CC) method, where an adaptive configuration interaction (ACI) wave function provides the external cluster amplitudes, named ACI-CC, is presented. By exploiting the connection between configuration interaction and coupled cluster through cluster analysis, the higher-order T3 and T4 terms obtained from ACI are used to augment the T1 and T2 amplitude equations from traditional coupled cluster. These higher-order contributions are kept frozen during the coupled cluster iterations and do not contribute to an increased cost with respect to CCSD. We have benchmarked this method on three closed-shell systems: beryllium dimer, carbonyl oxide, and cyclobutadiene, with good results compared to other corrected coupled cluster methods. In all cases, the inclusion of these external corrections improved upon the "gold standard" CCSD(T) results, indicating that ACI-CCSD(T) can be used to assess strong correlation effects in a system and as an inexpensive starting point for more complex external corrections

Differences in soft-sediment macrobenthic assemblages invaded by Caulerpa taxifolia compared to uninvaded habitats

Caulerpa taxifolia is a habitat-forming green alga that has invaded several temperate regions worldwide. Although C. taxifolia covers large areas of soft-sediment habitat, little is known about its effects on soft-sediment invertebrate assemblages. We compared soft-sediment macroinvertebrate assemblages in 2 estuaries in southeastern Australia invaded by C. taxifolia to examine 2 main predictions: (1) areas covered with C. taxifolia will have different assemblages compared to unvegetated sediment because infauna are inhibited but epifauna are facilitated, and (2) areas with C. taxifolia will have different assemblages compared to those with native seagrasses (Halophila ovalis and Zostera capricorni) because infauna are inhibited but epifauna are not. Multidimensional scaling and ANOSIM showed differences in invertebrate assemblages between all habitats. In C. taxifolia, infauna were less abundant and epifauna were more abundant compared to unvegetated sediment. However, when compared to native seagrasses, epifauna in C. taxifolia were more abundant than in H. ovalis in one estuary but less abundant than in Z. capricorni in another estuary, while infauna in C. taxifolia were less abundant than in both seagrass species. The consistently low infaunal abundance in C. taxifolia, irrespective of infaunal feeding mode, suggests C. taxifolia impacts infauna generally. Examination of environmental factors potentially responsible for the low abundance of infauna indicated that differences in redox potential (and associated chemical changes) may explain patterns in abundance of infauna among habitats. Our findings indicate that invasion by C. taxifolia causes important changes to soft-sediment macroinvertebrate assemblages and suggest that infauna may be particularly vulnerable to invasion because of changes to sediment chemistry

Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis.

Study Design: Systematic literature review. Objectives: The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis. Methods: A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed. Results: Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Conclusion: Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status

Multi-modales Biofeedback System zur Vorbeugung von Stürzen Multi-modal Biofeedback System for the Prevention of Falls

Das Biofeedback des Körperschwankens stellt eine Möglichkeit dar, Patienten mit statischen und dynamischen Gleichgewichtsproblemen alternative Sinnesreize zur Erlangung eines stabilen Gleichgewichts zur Verfügung zu stellen, was zu einer Verbesserung ihrer Lebensqualität führt. Das Biofeedback-System erzeugt mittels am Kopf befestigter Signalwandler auditive, vibro-taktile und vibro-vestibuläre Sinneseindrücke. Die Ergebnisse sowohl an jungen als auch an älteren Probanden ergaben, dass mit Hilfe des Biofeedbacks eine bemerkenswerte 40-60%ige Reduktion des Körperschwankens erzielt werden konnt

High-resolution definition of the Vibrio cholerae essential gene set with hidden Markov model–based analyses of transposon-insertion sequencing data

The coupling of high-density transposon mutagenesis to high-throughput DNA sequencing (transposon-insertion sequencing) enables simultaneous and genome-wide assessment of the contributions of individual loci to bacterial growth and survival. We have refined analysis of transposon-insertion sequencing data by normalizing for the effect of DNA replication on sequencing output and using a hidden Markov model (HMM)-based filter to exploit heretofore unappreciated information inherent in all transposon-insertion sequencing data sets. The HMM can smooth variations in read abundance and thereby reduce the effects of read noise, as well as permit fine scale mapping that is independent of genomic annotation and enable classification of loci into several functional categories (e.g. essential, domain essential or ‘sick’). We generated a high-resolution map of genomic loci (encompassing both intra- and intergenic sequences) that are required or beneficial for in vitro growth of the cholera pathogen, Vibrio cholerae. This work uncovered new metabolic and physiologic requirements for V. cholerae survival, and by combining transposon-insertion sequencing and transcriptomic data sets, we also identified several novel noncoding RNA species that contribute to V. cholerae growth. Our findings suggest that HMM-based approaches will enhance extraction of biological meaning from transposon-insertion sequencing genomic data