Of hummingbirds and helicopters: Hovering costs, competitive ability, and foraging strategies

Wing morphology and flight kinematics profoundly influence foraging costs and the overall behavioral ecology of hummingbirds. By analogy with helicopters, previous energetic studies have applied the momentum theory of aircraft propellers to estimate hovering costs from wing disc loading (WDL), a parameter incorporating wingspan (or length) and body mass. Variation in WDL has been used to elucidate differences either among hummingbird species in nectar-foraging strategies (e.g., territoriality, traplining) and dominance relations or among gender-age categories within species. We first demonstrate that WDL, as typically calculated, is an unreliable predictor of hovering (induced power) costs; predictive power is increased when calculations use wing length instead of wingspan and when actual wing stroke amplitudes are incorporated. We next evaluate the hypotheses that foraging strategy and competitive ability are functions of WDL, using our data in combination with those of published sources. Variation in hummingbird behavior cannot be easily classified using WDL and instead is correlated with a diversity of morphological and physiological traits. Evaluating selection pressures on hummingbird wings will require moving beyond wing and body mass measurements to include the assessment of the aerodynamic forces, power requirements, and power reserves of hovering, forward flight, and maneuvering. However, the WDLhelicopter dynamics model has been instrumental in calling attention to the importance of comparative wing morphology and related aerodynamics for understanding the behavioral ecology of hummingbirds

Bullous Contagious Livipetigo of the newly born (Pemphigus Neonatorum)

The disease known as pemphigus neonatorum or bullous contagious staphylococcic impetigo of the newly born has shown in most countries a tendency to increase in incidence since the war. Almost all maternity hospitals and wards that have been open for any length of time have had at least one epidemic in the last ten years. Brennemann (1928) writes: °Hospitals in which impetigo neonatorum does not occur either have no maternity wards or else do not recognise the disease.The disease is perhaps recognised more often than. it was, and some stress has been laid on it in the Central Midwives Board Reports, 1927 and 1934. Attention has been drawn to it much more in the last ten years in American literature. However, the significance of a few bullous spots on an otherwise normal, healthy baby a few days old is often missed, and before the resulting epidemic has ceased one or more deaths may have occurred. As a disease entity it is really only seen by the personnel of the ward nursery. Paediatricians and dermatologists see relatively few cases. This paper is an attempt to summarise the more recent literature, and to stress the significance of the first lesion appearing in the ward nursery. A practitioner seeing a child with healing lesions discharged one or two days before from hospital will know that the wards of that hospital are dangerous to babies born there in the next few days or weeks.. Irwin Rubell (1931) noted that in private practice cases were frequently encountered coming from various hospitals, and he states that epidemics are more common than one would suppose as so many are hushed up. In this country the midwife in attendance is bound to notify the infected case to the local supervising authority at once, and to disinfect herself and her appliances to the satisfaction of that authority. The disease, however, still seems to be increasing, and the probable reasons are (a) failure to recognise the nature of the disease, (b) inadequate cleanliness and sterility in the maternity department, (c) failure to recognise the significance of the first case, even if diagnosed, and (d) the tendency to hush the whole thing up. More and more cases go to maternity hospitals nowadays, and often the attendance has increased while the building has not. Overcrowding is a very definite predisposing factor.The two epidemics here described are of interest in that they present most of the usual features of the disease, and also bring out a few points hitherto inadequately stressed

Paved with Good Intentions: Title IX Campus Sexual Assault Proceedings and the Creation of Admissible Victim Statements

This Comment argues that campuses should, in the course of their Title IX proceedings, ensure that anyone who takes a potentially admissible statement from a survivor has received trauma-informed interview training. Trauma-informed interviewing acknowledges the physiological effect of trauma on survivors, the impact that it can have on their ability to recall facts and details, and the limits and possibilities of obtaining information from such witnesses. In addition, campuses should limit the number of individuals who take statements from survivors and record the victim’s statements. These improvements will create statements of higher evidentiary quality. It will also mitigate the emotional harm to survivors, helping to ensure their continued cooperation with prosecutors and law enforcement. To understand the process of investigating Title IX complaints and how the procedures that started on campus can impact a future criminal investigation, experts on both sides of the “ivory tower” were interviewed, including law enforcement officers, prosecutors, and an expert in Title IX jurisprudence. Part I describes the research methodology utilized, the process of finding and interviewing the research subjects selected, and the research subjects’ credentials. Part II reviewsTitle IX disciplinary proceedings and applicable laws. Part III explains a typical interview process, and how it does not account for the trauma inherent in sexual assault or the unique context in which a campus sexual assault occurs. This creates admissible statements of dubious value and quality, which can be used to impeach a victim in a future criminal case. Part IV outlines a new way forward, which allows survivors to participate in the campus disciplinary process while mitigating the harm to both to themselves and to a future criminal prosecution. Here, advances in trauma-informed interviewing, the need to mandate such training for all personnel who conduct a Title IX proceeding on campus, and the necessity of accurately documenting the survivor’s statement, are explored. In addition, recent federal actions that support trauma-informed interview practices as a necessary component of Title IX compliance are described

Going with the grain : an experiment in people-sensitive preaching

https://place.asburyseminary.edu/ecommonsatsdissertations/1085/thumbnail.jp

Modulation instability, Akhmediev Breathers and continuous wave supercontinuum generation

Numerical simulations of the onset phase of continuous wave supercontinuum generation from modulation instability show that the structure of the field as it develops can be interpreted in terms of the properties of Akhmediev Breathers. Numerical and analytical results are compared with experimental measurements of spectral broadening in photonic crystal fiber using nanosecond pulsesComment: 22 pages, 6 figure

Magnetic shielding and exotic spin-dependent interactions

Experiments searching for exotic spin-dependent interactions typically employ magnetic shielding between the source of the exotic field and the interrogated spins. We explore the question of what effect magnetic shielding has on detectable signals induced by exotic fields. Our general conclusion is that for common experimental geometries and conditions, magnetic shields should not significantly reduce sensitivity to exotic spin-dependent interactions, especially when the technique of comagnetometry is used. However, exotic fields that couple to electron spin can induce magnetic fields in the interior of shields made of a soft ferro- or ferrimagnetic material. This induced magnetic field must be taken into account in the interpretation of experiments searching for new spin-dependent interactions and raises the possibility of using a flux concentrator inside magnetic shields to amplify exotic spin-dependent signals.Comment: 8 pages, 5 figure