Conceptual Issues and Methodology in Kin-recognition Research: A Critical Discussion

We operationally define kin-recognition and discuss methodological and conceptual issues that arise in its study, citing examples from the literature that illustrate particular points. We define and examine three components of kin-recognition (expression, perception, and action), and discuss why some experimental designs fail to distinguish among the components. We also point out ways that experimental designs might be modified to unlink the components. We discuss three general issues central to assays of kin-recognition: the functional significance of assays, multiple- and single-behavior assays, and potential biases in assays. The potential biases we consider are nonblind behavioral assays and the pooling of dependent data. We also examine negative results and, in particular, those factors that can produce negative results when recognition ability is present. Finally, we discuss kin-recognition in natural contexts, emphasizing the potential dangers of uncritically extrapolating the results of laboratory studies to field contexts.     

Evaluation of Viral Inactivation on Dry Surface by High Peak Power Microwave (HPPM) Exposure

Previous research has shown that virus infectivity can be dramatically reduced by radio frequency exposure in the gigahertz (GHz) frequency range. Given the worldwide SARS-CoV-2 pandemic, which has caused over 1 million deaths and has had a profound global economic impact, there is a need for a noninvasive technology that can reduce the transmission of virus among humans. RF is a potential wide area-of-effect viral decontamination technology that could be used in hospital rooms where patients are expelling virus, in grocery and convenience stores where local populations mix, and in first responder settings where rapid medical response spans many potentially infected locations within hours. In this study, we used bovine coronavirus (BCoV) as a surrogate of SARS-CoV-2 and exposed it to high peak power microwave (HPPM) pulses at four narrowband frequencies: 2.8, 5.6, 8.5, and 9.3 GHz. Exposures consisted of 2 µs pulses delivered at 500 Hz, with pulse counts varied by decades between 1 and 10,000. The peak field intensities (i.e. the instantaneous power density of each pulse) ranged between 0.6 and 6.5 MW/m², depending on the microwave frequency. The HPPM exposures were delivered to plastic coverslips containing BCoV dried on the surface. Hemagglutination (HA) and cytopathic effect analyses were performed 6 days after inoculation of host cells to assess viral infectivity. No change in viral infectivity was seen with increasing dose (pulse number) across the tested frequencies. Under all conditions tested, exposure did not reduce infectivity more than 1.0 log_10. For the conditions studied, high peak power pulsed RF exposures in the 2–10 GHz range appear ineffective as a virucidal approach for hard surface decontamination. © 2023 Bioelectromagnetics Society.     

Effects of birthplace and individual genetic admixture on lung volume and exercise phenotypes of Peruvian Quechua

Forced vital capacity (FVC) and maximal exercise response were measured in two populations of Peruvian males (age, 18-35 years) at 4,338 m who differed by the environment in which they were born and raised, i.e., high altitude (Cerro de Pasco, Peru, BHA, n = 39) and sea level (Lima, Peru, BSL, n = 32). BSL subjects were transported from sea level to 4,338 m, and were evaluated within 24 hr of exposure to hypobaric hypoxia. Individual admixture level (ADMIX, % Spanish ancestry) was estimated for each subject, using 22 ancestry-informative genetic markers and also by skin reflectance measurement (MEL). Birthplace accounted for the approximately 10% larger FVC (P < 0.001), approximately 15% higher maximal oxygen consumption (VO(2)max, ml.min(-1).kg(-1)) (P < 0.001), and approximately 5% higher arterial oxygen saturation during exercise (SpO(2)) (P < 0.001) of BHA subjects. ADMIX was low in both study groups, averaging 9.5 +/- 2.6% and 2.1 +/- 0.3% in BSL and BHA subjects, respectively. Mean underarm MEL was significantly higher in the BSL group (P < 0.001), despite higher ADMIX. ADMIX was not associated with any study phenotype, but study power was not sufficient to evaluate hypotheses of genetic adaptation via the ADMIX variable. MEL and FVC were positively correlated in the BHA (P = 0.035) but not BSL (P = 0.335) subjects. However, MEL and ADMIX were not correlated across the entire study sample (P = 0.282). In summary, results from this study emphasize the importance of developmental adaptation to high altitude. While the MEL-FVC correlation may reflect genetic adaptation to high altitude, study results suggest that alternate (environmental) explanations be considered.     

Effects of temperature and humidity on the development of eggs of Toxocara canis under laboratory conditions

The influence of temperature and humidity on the survival and development of Toxocara canis eggs in an in vitro model system was investigated. Two soil samples were inoculated with T. canis eggs and maintained at 3% and 50% humidity and temperatures of 19-24 degrees C. Nine soil samples were inoculated with T. canis eggs of which three samples were kept at 4 degrees C with humidities at 3%, 15%, and 30%; three were maintained at 21 degrees C and three more were incubated at 34 degrees C, and at the same three humidity levels. Samples were monitored every 7 days for a total of 2 months, for the presence and development of eggs. With increasing temperature, the number of eggs undergoing development increased (P<0.01); the number of deformed eggs decreased, the number of infective eggs increased (P<0.01), and egg maturation was accelerated. A decrease in the survival of infective eggs occurred at 34 degrees C. An increase in humidity produced a rise in the number of developed eggs at all three temperatures (P<0.01). This study suggests that elevated temperatures accelerated the development as well as the degradation of eggs of T. canis, whereas the range in humidity was directly correlated with egg development.     

Neuronal migration is transiently delayed by prenatal exposure to intermittent hypoxia

BACKGROUND: Neonatal neurodevelopment is influenced by a variety of external factors, although the mechanisms responsible are poorly understood. Prenatal hypoxia, from physiological or chemical sources, can have no discernible effect, or can result in a broad spectrum of abnormalities. METHODS: To mimic some of the maternal effects of smoking, we developed a model that investigates the effects of intermittent hypoxia (IH), with or without concurrent nicotine in timed pregnant Sprague-Dawley rats. RESULTS: We found no significant differences between litter sizes or birthweight of pups from any treatment group, but animals exposed to IH (with or without nicotine) showed long term diminished body weights. Animals subjected to IH consistently showed a transient delay in neuronal migration early in the postpartum period, which was amplified by concurrent nicotine administration. We observed increased c-Abl protein levels in animals from the IH treatment groups. Multiple proteins involved in the intricate control of neuronal migration were also altered in response to this treatment, primarily the downstream targets of c-Abl: Cdk5, p25, and the cytoskeletal elements neurofilament H and F-actin and catalase. Catalase activity and protein levels, already elevated in response to IH, were further amplified by simultaneous nicotine exposure. CONCLUSIONS: This new model provides a novel system for investigating the effects of low grade IH in the developing brain and suggests that concurrent nicotine further aggravates many of the deleterious effects of IH.     

Nest Entrance Marking with Colony Specific Odors by the Bumble Bee Bombus occidentalis (Hymenoptera: Apidae)

We investigated the ability of naturally foraging female bumble bees (Bombus occidentalis) to recognize their nest entrance in the field. In a blind binary-choice paradigm, females discriminated between nest entrances tipped with caps from their own nest entrances and entrances tipped with caps previously associated with foreign heterospecific or foreign conspecific colonies. Washing caps in organic solvents eliminated the manifestation of this nest-entrance recognition and significantly decreased the episodes of antennating caps. These results indicate that bees deposit colony-specific chemicals on nest entrances that are later perceived via contact chemoreception. Females treated foreign heterospecific and foreign conspecific caps similarly, suggesting that bees may not assess or respond to the degree of similarity between their own colony odor and a foreign colony odor.     

Identifying critical habitat of the endangered vaquita (Phocoena sinus) with regional δ13C and δ15N isoscapes of the Upper Gulf of California,Mexico

The vaquita (Phocoena sinus) is the world's most endangered cetacean and has experienced a 60% reduction in the size of its population in the past decade. Knowledge of its basic ecology is essential for developing successful management plans to protect and conserve this species. In this study, we identified vaquita foraging areas by creating an isoscape of the Upper Gulf of California (UGC) based on sediment and zooplankton carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope values. Our results confirm that this species is confined to the western region of the UGC, which is characterized by relatively high δ¹⁵N values (sediments: 10.2‰ ± 2.0‰, zooplankton: 15.8‰ ± 1.3‰), higher sea surface temperatures (～16°C–25°C), higher concentrations of silt in sediments, and the highest turbidity. In contrast, the eastern region of the UGC had relatively low sediment (7.7‰ ± 2.4‰) and zooplankton (14.6‰ ± 1.0‰) δ¹⁵N values, and the highest concentrations of sand in sediments. Our approach is an effective use of marine isoscapes over a small spatial scale (<200 km) to identify the environmental characteristics that define the critical habitat for an extremely endangered marine mammal.