Duración y éxito de eclosión en diferentes tamaños de nidadas de Crocodylus moreletii (Crocodylia: Crocodilidae)

Background. The Crocodylia begin their life by overcoming the incubation stage with group hatching. Incubation temperature is important for the development of the embryos and the duration of the hatching process, during which they emit sounds. Goals. The effect of the size of the clutch on the duration and success of hatching is reported for the first time, and the hatching process is described. Methods. We used four clutches supplied by the "Granja de Lagartos" farm in Tabasco, Mexico, from the 2010 breeding season, and each was distributed in containers to integrate three clutches of different size: large (15 eggs), medium (nine eggs), and small (one egg). We monitored the temperature, relative humidity, and the number of eggs hatched in each clutch. The duration of hatching and the incubation period were statistically compared, as well as hatching success among the three brood sizes. We made sure that incubation conditions were the same for all boxes. Results. The small clutches (? = 3340, ± 2794 min) and the medium-sized ones (? = 1844 ± 476 min) took less minutes to hatch, and both took less time than the large clutches (? = 9431 ± 768 min). The hatchings began with the vocalization of pre-hatching calls, heard up to a week before eclosion. Conclusions. The size of the clutch influences the duration of hatching, but is not related to hatching success.  Antecedentes. Los Crocodylia inician su historia de vida al superar la etapa de incubación con la eclosión en grupo. La temperatura de incubación es importante para el desarrollo de los embriones y el proceso de eclosión, durante el cual emiten sonidos. Objetivos. Reportar la influencia del tamaño de la nidada sobre la duración y el éxito de eclosión, y describir dicho proceso. Métodos. Se emplearon cuatro nidadas de Crocodylus moreletii de la Unidad de Manejo para la Conservación de la Vida Silvestre (UMA) Granja de Lagartos, en Tabasco, México. Con estas se integraron tres nidadas de diferente tamaño: grande (15 huevos), mediana (9 huevos) y pequeña (un huevo). Se monitorizó la temperatura, la humedad relativa y el número de huevos eclosionados y se compararon estadísticamente la duración de las eclosiones y el periodo de incubación, así como el éxito de la eclosión entre los tres tamaños de nidadas. Por último, se verificó que las condiciones de incubación fueran iguales para todas las nidadas. Resultados. Las nidadas pequeñas (? = 3340 ± 2794) y las medianas (? = 1844 ± 476) tardaron menos minutos en eclosionar en comparación con las nidadas grandes (? = 9431 ± 768). Mientras que el éxito de la eclosión (expresado en porcentaje) y la duración en días del periodo de incubación no mostraron diferencias entre los tres tamaños de nidada. Las eclosiones iniciaron con la emisión de los llamados preeclosionales, los cuales se escucharon una semana antes de la eclosión. Conclusiones. El tamaño de nidada influye en la duración de la eclosión, pero no influye sobre su éxito

Temporal Processing of Vibratory Communication Signals at the Level of Ascending Interneurons in Nezara viridula (Hemiptera: Pentatomidae)

During mating, males and females of N. viridula (Heteroptera: Pentatomidae) produce sex- and species-specific calling and courtship substrate-borne vibratory signals, grouped into songs. Recognition and localization of these signals are fundamental for successful mating. The recognition is mainly based on the temporal pattern, i.e. the amplitude modulation, while the frequency spectrum of the signals usually only plays a minor role. We examined the temporal selectivity for vibratory signals in four types of ascending vibratory interneurons in N. viridula. Using intracellular recording and labelling technique, we analyzed the neurons' responses to 30 pulse duration/interval duration (PD/ID) combinations. Two response arrays were created for each neuron type, showing the intensity of the responses either as time-averaged spike counts or as peak instantaneous spike rates. The mean spike rate response arrays showed preference of the neurons for short PDs (below 600 ms) and no selectivity towards interval duration; while the peak spike rate response arrays exhibited either short PD/long ID selectivity or no selectivity at all. The long PD/short ID combinations elicited the weakest responses in all neurons tested. No response arrays showed the receiver preference for either constant period or duty cycle. The vibratory song pattern selectivity matched the PD of N. viridula male vibratory signals, thus pointing to temporal filtering for the conspecific vibratory signals already at level of the ascending interneurons. In some neurons the responses elicited by the vibratory stimuli were followed by distinct, regular oscillations of the membrane potential. The distance between the oscillation peaks matched the temporal structure of the male calling song, indicating a possible resonance based mechanism for signal recognition

Cold War : a Transnational Approach to a Global Heritage

Although within living memory, many countries now consider their surviving Cold War architecture as part of their heritage. It can even be a priority for heritage managers given that significant buildings are often suitable for reuse while extensive ‘brownfield’ sites such as airfields can be used for large-scale redevelopment. In a number of countries whose work we refer to here (notably the United Kingdom and elsewhere in Europe), agencies responsible for managing their country’s heritage have approached this priority by creating national inventories of sites and buildings with a view to taking informed decisions on their future. This paper presents the argument that the wider international context of the Cold War provides a more appropriate (or additional, higher-level) framework for such decision making. Such a ‘transnational’ approach would allow the comparison of similar (e.g. European) sites not merely within national borders but across the full extent of their western NATO1 deployment in Europe and North America. Taking this approach would also allow comparison with related sites in countries that formed part of the eastern-bloc Warsaw Pact.2 After outlining some examples of how national agencies have approached their Cold War heritage, this paper presents the four stages of this transnational approach making provision for an improved understanding and management of Cold War heritage sites wherever they occur. With a specific focus on the direct comparison between England and Russia, and also referring to sites surviving elsewhere within the former NATO and Warsaw Pact regions, as well as the United States, we argue that this four-stage approach: provides new understandings of a complex archaeological and architectural record; gives fresh perspectives on significance; and (importantly in a time of geopolitical instability) does so in a spirit of cooperation and friendship

Whispering to the Deaf: Communication by a Frog without External Vocal Sac or Tympanum in Noisy Environments

Atelopus franciscus is a diurnal bufonid frog that lives in South-American tropical rain forests. As in many other frogs, males produce calls to defend their territories and attract females. However, this species is a so-called “earless” frog lacking an external tympanum and is thus anatomically deaf. Moreover, A. franciscus has no external vocal sac and lives in a sound constraining environment along river banks where it competes with other calling frogs. Despite these constraints, male A. franciscus reply acoustically to the calls of conspecifics in the field. To resolve this apparent paradox, we studied the vocal apparatus and middle-ear, analysed signal content of the calls, examined sound and signal content propagation in its natural habitat, and performed playback experiments. We show that A. franciscus males can produce only low intensity calls that propagate a short distance (<8 m) as a result of the lack of an external vocal sac. The species-specific coding of the signal is based on the pulse duration, providing a simple coding that is efficient as it allows discrimination from calls of sympatric frogs. Moreover, the signal is redundant and consequently adapted to noisy environments. As such a coding system can be efficient only at short-range, territory holders established themselves at short distances from each other. Finally, we show that the middle-ear of A. franciscus does not present any particular adaptations to compensate for the lack of an external tympanum, suggesting the existence of extra-tympanic pathways for sound propagation

(Im)material Culture : Towards an Archaeology of Cybercrime

Cybercrime is ubiquitous. People now inhabit a digital environment comprising permanent risk, exponential threats, and multiple virtual/physical harms, forming a global community of malefactors and the criminally exploited. The purpose of this paper is two-fold. First, through an archaeological lens, to characterize the new materiality of cybercrime (including its artefacts and architecture alongside digital/virtual manifestations). And second, to explore the potential for new perspectives on cybercrime borne out of this archaeological approach. In short: what is the archaeology of cybercrime and can new understandings emerge from an archaeological perspective? In undertaking this research we also challenge the long-held presumption that non-physical traces cannot be studied archaeologically. It is our contention that they can

The impact of sexual harassment on job satisfaction, turnover intentions, and absenteeism: findings from Pakistan compared to the United States

The purpose of this study was to compare and contrast how differences in perceptions of sexual harassment impact productive work environments for employees in Pakistan as compared to the US; in particular, how it affects job satisfaction, turnover, and/or absenteeism. This study analyzed employee responses in Pakistan (n = 146) and the United States (n = 102, 76) using questionnaire data. Significant results indicated that employees who were sexually harassed reported (a) a decrease in job satisfaction (b) greater turnover intentions and (c) a higher rate of absenteeism. Cross-cultural comparisons indicated that (a) Pakistani employees who were sexually harassed had greater job dissatisfaction and higher overall absenteeism than did their US counterparts and (b) Pakistani women were more likely to use indirect strategies to manage sexual harassment than were US targets

Ecoacoustics and multispecies semiosis: naming, semantics, semiotic characteristics, and competencies

Biosemiotics to date has focused on the exchange of signals between organisms, in line with bioacoustics; consideration of the wider acoustic environment as a semiotic medium is under-developed. The nascent discipline of ecoacoustics, that investigates the role of environmental sound in ecological processes and dynamics, fills this gap. In this paper we introduce key ecoacoustic terminology and concepts in order to highlight the value of ecoacoustics as a discipline in which to conceptualise and study intra- and interspecies semiosis. We stress the inherently subjective nature of all sensory scapes (vivo-, land-, vibro- and soundscapes) and propose that they should always bear an organismic attribution. Key terms to describe the sources (geophony, biophony, anthropophony, technophony) and scales (sonotopes, soundtopes, sonotones) of soundscapes are described. We introduce epithets for soundscapes to point to the degree to which the global environment is implicated in semiosis (latent, sensed and interpreted soundscapes); terms for describing key ecological structures and processes (acoustic community, acoustic habitat, ecoacoustic events) and examples of ecoacoustic events (choruses and noise) are described. The acoustic eco-field is recognized as the semiotic model that enables soniferous species to intercept core resources like food, safety and roosting places. We note that whilst ecoacoustics to date has focused on the critical task of the development of metrics for application in conservation and biodiversity assessment, these can be enriched by advancing conceptual and theoretical foundations. Finally, the mutual value of integrating ecoacoustic and biosemiotics perspectives is considered