Aggregation Behavior of a Willow Flea Beetle, \u3ci\u3eAltica Subplicata\u3c/i\u3e (Coleoptera: Chrysomelidae)

This study examined the aggregation behavior of a specialist insect herbivore, Altica subplicata (Coleoptera: Chrysomelidae), on its host plant, Salix cordata. Mark-recapture experiments were conducted in patches of S. cordata growing along the shores of Lake Huron. Beetles aggregated on individual host plants, but did not aggregate in larger areas containing many host plants. Plants colonized by marked beetles had significantly higher abundances of unmarked beetles than did plants that were not colonized by marked beetles. Experimental manipulations of the number of beetles present on plants showed that colonization rates by marked beetles were higher on plants with conspecifics than on plants which had all beetles removed the previous day. The sex of beetles, however, did not influence colonization behavior; both male and female beetles colonized plants regardless of the sex of beetles already present on plants. These results are discussed with respect to possible explanations for aggregation, and the role of aggregation and movement in influencing insect distributions

Aggregation Behavior of a Willow Flea Beetle, \u3ci\u3eAltica Subplicata\u3c/i\u3e (Coleoptera: Chrysomelidae)

This study examined the aggregation behavior of a specialist insect herbivore, Altica subplicata (Coleoptera: Chrysomelidae), on its host plant, Salix cordata. Mark-recapture experiments were conducted in patches of S. cordata growing along the shores of Lake Huron. Beetles aggregated on individual host plants, but did not aggregate in larger areas containing many host plants. Plants colonized by marked beetles had significantly higher abundances of unmarked beetles than did plants that were not colonized by marked beetles. Experimental manipulations of the number of beetles present on plants showed that colonization rates by marked beetles were higher on plants with conspecifics than on plants which had all beetles removed the previous day. The sex of beetles, however, did not influence colonization behavior; both male and female beetles colonized plants regardless of the sex of beetles already present on plants. These results are discussed with respect to possible explanations for aggregation, and the role of aggregation and movement in influencing insect distributions

Theoretical foundations of the sound analog membrane potential that underlies coincidence detection in the barn owl

A wide variety of neurons encode temporal information via phase-locked spikes. In the avian auditory brainstem, neurons in the cochlear nucleus magnocellularis (NM) send phase-locked synaptic inputs to coincidence detector neurons in the nucleus laminaris (NL) that mediate sound localization. Previous modeling studies suggested that converging phase-locked synaptic inputs may give rise to a periodic oscillation in the membrane potential of their target neuron. Recent physiological recordings in vivo revealed that owl NL neurons changed their spike rates almost linearly with the amplitude of this oscillatory potential. The oscillatory potential was termed the sound analog potential, because of its resemblance to the waveform of the stimulus tone. The amplitude of the sound analog potential recorded in NL varied systematically with the interaural time difference (ITD), which is one of the most important cues for sound localization. In order to investigate the mechanisms underlying ITD computation in the NM-NL circuit, we provide detailed theoretical descriptions of how phase-locked inputs form oscillating membrane potentials. We derive analytical expressions that relate presynaptic, synaptic, and postsynaptic factors to the signal and noise components of the oscillation in both the synaptic conductance and the membrane potential. Numerical simulations demonstrate the validity of the theoretical formulations for the entire frequency ranges tested (1–8 kHz) and potential effects of higher harmonics on NL neurons with low best frequencies (<2 kHz)

Public perceptions of drinking water: A postal survey of residents with private water supplies

Background: In Canada, the legal responsibility for the condition of private water supplies, including private wells and cisterns, rests with their owners. However, there are reports that Canadians test these water supplies intermittently and that treatment of such water is uncommon. An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An understanding of the perceptions and needs of Canadians served by private water supplies is essential, as it would enable public health professionals to better target public education and drinking water policy. The purpose of this study was to investigate the public perceptions of private water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public education and outreach strategies within the population. Methods: A cross-sectional postal survey of 246 residences with private water supplies was conducted in May 2004. Questions pertained to the perceptions of water quality and alternative water sources, water testing behaviours and the self-identified need for further information. Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and 13% of respondents, respectively. Although respondents rated their water quality highly, 80% also had concerns with its safety. The most common concerns pertained to bacterial and chemical contamination of their water supply and its potential negative effect on health. Approximately 56% and 61% of respondents used in-home treatment devices and bottled water within their homes, respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared to regular tap water. Testing of private water supplies was performed infrequently: 8% of respondents tested at a frequency that meets current provincial guidelines. Two-thirds of respondents wanted more information on various topics related to private water supplies. Flyers and newspapers were the two media reported most likely to be used. Conclusion: Although respondents rated their water quality highly, the majority had concerns regarding the water from their private supply, and the use of bottled water and water treatment devices was extensive. The results of this study suggest important lines of inquiry and provide support and input for public education programs, particularly those related to private water testing, in this population

In-air hearing of a diving duck: A comparison of psychoacoustic and auditory brainstem response thresholds

Auditory sensitivity was measured in a species of diving duck that is not often kept in captivity, the lesser scaup. Behavioral (psychoacoustics) and electrophysiological [the auditory brainstem response (ABR)] methods were used to measure in-air auditory sensitivity, and the resulting audiograms were compared. Both approaches yielded audiograms with similar U-shapes and regions of greatest sensitivity (2000-3000 Hz). However, ABR thresholds were higher than psychoacoustic thresholds at all frequencies. This difference was least at the highest frequency tested using both methods (5700 Hz) and greatest at 1000 Hz, where the ABR threshold was 26.8 dB higher than the behavioral measure of threshold. This difference is commonly reported in studies involving many different species. These results highlight the usefulness of each method, depending on the testing conditions and availability of the animals

Biophysical basis of the sound analog membrane potential that underlies coincidence detection in the barn owl

Interaural time difference (ITD), or the difference in timing of a sound wave arriving at the two ears, is a fundamental cue for sound localization. A wide variety of animals have specialized neural circuits dedicated to the computation of ITDs. In the avian auditory brainstem, ITDs are encoded as the spike rates in the coincidence detector neurons of the nucleus laminaris (NL). NL neurons compare the binaural phase-locked inputs from the axons of ipsi- and contralateral nucleus magnocellularis (NM) neurons. Intracellular recordings from the barn owl's NL in vivo showed that tonal stimuli induce oscillations in the membrane potential. Since this oscillatory potential resembled the stimulus sound waveform, it was named the sound analog potential (Funabiki et al., 2011). Previous modeling studies suggested that a convergence of phase-locked spikes from NM leads to an oscillatory membrane potential in NL, but how presynaptic, synaptic, and postsynaptic factors affect the formation of the sound analog potential remains to be investigated. In the accompanying paper, we derive analytical relations between these parameters and the signal and noise components of the oscillation. In this paper, we focus on the effects of the number of presynaptic NM fibers, the mean firing rate of these fibers, their average degree of phase-locking, and the synaptic time scale. Theoretical analyses and numerical simulations show that, provided the total synaptic input is kept constant, changes in the number and spike rate of NM fibers alter the ITD-independent noise whereas the degree of phase-locking is linearly converted to the ITD-dependent signal component of the sound analog potential. The synaptic time constant affects the signal more prominently than the noise, making faster synaptic input more suitable for effective ITD computation

Predictors of return to driving after stroke

OBJECTIVE: While returning to driving is a major concern for many stroke survivors, predicting who will return to driving after a stroke is often difficult for rehabilitation professionals. The primary aim of this study was to identify patient factors present at admission to an inpatient rehabilitation hospital that can be used to identify which patients with acute stroke will and will not return to driving. DESIGN: After comparing returners and non-returners on demographic and clinical characteristics, a logistic regression model with return to driving as the outcome variable was built using the backward stepwise method. RESULTS: Thirty-one percent (48/156) of patients who had been driving before their stroke had returned to driving six months post-stroke. The final regression model, using FIM cognition and lower extremity Motricity Index scores, predicted the driving outcome with an accuracy of 75% (107/143). CONCLUSIONS: Patients with lower FIM cognition and lower extremity Motricity Index scores at admission to inpatient rehabilitation are less likely to return to driving at six months. This model could be used by rehabilitation professionals to help counsel patients and their families and focus treatment goals

Асинхронный электропривод экструдера полипропиленовой нити

В данной выпускной квалификационной работе рассматривается система экструдера линии TL – 60. Проведены исследования работы электропривода экструдера в динамических режимах работы. В основной части работы рассмотрены: объект автоматизации, техно-логический процесс, требования к электроприводу, функциональная схема системы экструдера, структурные схемы экструдера и регулируемого электропривода (РЭП). Расчетная часть включает в себя расчет параметров силовой цепи, характеристик системы векторного управления и тиристорного преобразователя, проверку области существования электромеханических характеристик привода, а также синтез структуры системы регулирования диаметра и их анализ.This qualification system is graduation extruder line TL-60. Studies of the work of the electric drive of the extruder in dynamic modes. In the main part of the work considered: Automation object, techno-logical process, drive requirements, functional scheme of the extruder, extruder structural schemes and controlled electric drive (CED). Estimated portion includes the calculation of parameters of the power circuit, vector control and system characteristics of the thyristor converter, check the field existence of electromechanical actuator characteristics, as well as the regulatory system structure synthesis and analysis of diameter

Calcium Binding Protein-Like Immunoreactivity Labels the Terminal Field of Nucleus Laminaris of the Barn Owl

Nucleus laminaris (NL) is the site at which the timing of sounds arriving in the 2 ears is compared in the auditory system of the barn owl. Earlier studies have reported vitamin D-dependent calcium binding protein (CaBP)-like immunoreactivity in the somata of NL. We report here that CaBP-like immunoreactivity stains the terminal field of NL. The specific CaBP immunoreactivity is localized to a dense plexus of fibers that have bouton-like swellings, usually around unstained somata. This type of immunoreactivity is found in a restricted portion of the central nucleus of the inferior colliculus (ICc), in the anterior division of the ventral lateral lemniscal complex (VLVA), and in the superior olivary nucleus (SO), all of which have been shown by anterograde transport of 3H-proline to be innervated by NL. The immunoreactivity is absent from the posterior division of ventral lateral lemniscal complex and from the region that surrounds the portion of ICc innervated by NL. A restricted lesion in NL results in a localized deficit in immunoreactivity in those regions of ICc and VLVA that are known to be innervated by the lesioned area of NL. In adjacent sections processed by the Fink-Heimer method, degenerating axons are present in the region of the deficit in immunoreactivity