3,264 research outputs found
Previously unpublished Odonata records from Sarawak, Borneo : part 2, Kubah National Park
Records of Odonata from Kubah National Park, near Kuching in west Sarawak, are presented. Eighty-five species are known from the national park. Notable records include Drepanosticta drusilla, Rhinocypha species cf spinifer, Bornagriolestes species, Anaciaeschna species and Macromidia genialis erratica
Functional and structural changes throughout the auditory system following congenital and early-onset deafness: implications for hearing restoration
The absence of auditory input, particularly during development, causes widespread changes in the structure and function of the auditory system, extending from peripheral structures into auditory cortex. In humans, the consequences of these changes are far-reaching and often include detriments to language acquisition, and associated psychosocial issues.Much of what is currently known about the nature of deafness-related changes to auditory structures comes from studies of congenitally deaf or early-deafened animal models. Fortunately, the mammalian auditory system shows a high degree of preservation among species, allowing for generalization from these models to the human auditory system. This review begins with a comparison of common methods used to obtain deaf animal models, highlighting the specific advantages and anatomical consequences of each. Some consideration is also given to the effectiveness of methods used to measure hearing loss during and following deafening procedures. The structural and functional consequences of congenital and early-onset deafness have been examined across a variety of mammals. This review attempts to summarize these changes, which often involve alteration of hair cells and supporting cells in the cochleae, and anatomical and physiological changes that extend through subcortical structures and into cortex. The nature of these changes is discussed, and the impacts to neural processing are addressed. Finally, long-term changes in cortical structures are discussed, with a focus on the presence or absence of cross-modal plasticity. In addition to being of interest to our understanding of multisensory processing, these changes als
Metacarpophalangeal Pattern Profile Analysis in Clinical Genetics: An Applied Anthropometric Method
The hand is a complex anatomical structure with the component bones susceptible to a combination of environmental and genetic factors that may affect the bone length and width. The alterations may involve a single bone or specific group of bones. The metacarpophalangeal pattern profile (MCPP) developed by Poznanski, Garn, and others (Poznanski et al. Birth Defects VIII (5): 125–131, 1972) is a graphic representation of the relative lengthening and shortening of the 19 tubular bones of the hand useful for diagnosis, comparison of dissimilar patients, and gene carrier detection. The profile hand bone measurements are derived from posteroanterior hand radiographs and are standardized for age and sex. Specific profiles have been developed for several syndromes. Therefore, MCPP analysis has developed from a method of describing changes in the hand to a technique useful in assigning a diagnosis to a specific syndrome and evaluation of skeletal development. The current status of MCPP analysis in clinical genetics, particularly with the Prader-Labhart-Willi and Sotos syndromes, is discussed
High-Field Functional Imaging of Pitch Processing in Auditory Cortex of the Cat.
The perception of pitch is a widely studied and hotly debated topic in human hearing. Many of these studies combine functional imaging techniques with stimuli designed to disambiguate the percept of pitch from frequency information present in the stimulus. While useful in identifying potential pitch centres in cortex, the existence of truly pitch-responsive neurons requires single neuron-level measures that can only be undertaken in animal models. While a number of animals have been shown to be sensitive to pitch, few studies have addressed the location of cortical generators of pitch percepts in non-human models. The current study uses high-field functional magnetic resonance imaging (fMRI) of the feline brain in an attempt to identify regions of cortex that show increased activity in response to pitch-evoking stimuli. Cats were presented with iterated rippled noise (IRN) stimuli, narrowband noise stimuli with the same spectral profile but no perceivable pitch, and a processed IRN stimulus in which phase components were randomized to preserve slowly changing modulations in the absence of pitch (IRNo). Pitch-related activity was not observed to occur in either primary auditory cortex (A1) or the anterior auditory field (AAF) which comprise the core auditory cortex in cats. Rather, cortical areas surrounding the posterior ectosylvian sulcus responded preferentially to the IRN stimulus when compared to narrowband noise, with group analyses revealing bilateral activity centred in the posterior auditory field (PAF). This study demonstrates that fMRI is useful for identifying pitch-related processing in cat cortex, and identifies cortical areas that warrant further investigation. Moreover, we have taken the first steps in identifying a useful animal model for the study of pitch perception
Modified Origins of Cortical Projections to the Superior Colliculus in the Deaf: Dispersion of Auditory Efferents.
Following the loss of a sensory modality, such as deafness or blindness, crossmodal plasticity is commonly identified in regions of the cerebrum that normally process the deprived modality. It has been hypothesized that significant changes in the patterns of cortical afferent and efferent projections may underlie these functional crossmodal changes. However, studies of thalamocortical and corticocortical connections have refuted this hypothesis, instead revealing a profound resilience of cortical afferent projections following deafness and blindness. This report is the first study of cortical outputs following sensory deprivation, characterizing cortical projections to the superior colliculus in mature cats
Origins of thalamic and cortical projections to the posterior auditory field in congenitally deaf cats.
Crossmodal plasticity takes place following sensory loss, such that areas that normally process the missing modality are reorganized to provide compensatory function in the remaining sensory systems. For example, congenitally deaf cats outperform normal hearing animals on localization of visual stimuli presented in the periphery, and this advantage has been shown to be mediated by the posterior auditory field (PAF). In order to determine the nature of the anatomical differences that underlie this phenomenon, we injected a retrograde tracer into PAF of congenitally deaf animals and quantified the thalamic and cortical projections to this field. The pattern of projections from areas throughout the brain was determined to be qualitatively similar to that previously demonstrated in normal hearing animals, but with twice as many projections arising from non-auditory cortical areas. In addition, small ectopic projections were observed from a number of fields in visual cortex, including areas 19, 20a, 20b, and 21b, and area 7 of parietal cortex. These areas did not show projections to PAF in cats deafened ototoxically near the onset of hearing, and provide a possible mechanism for crossmodal reorganization of PAF. These, along with the possible contributions of other mechanisms, are considered
The relational ethics of conflict and identity
The contemporary psychoanalytically inflected vocabulary of relational ethics centres on acknowledgement, witnessing and responsibility. It has become an important code for efforts to connect with otherness across fractures of hurt, oppression and suffering. One can see the deployment of this vocabulary to challenge patterns of exclusion and dehumanisation in zones of intense political conflict in many situations in which destructive hatred reigns. This paper traces some of the use of and disputes over this ‘acknowledgement-based’ relational ethics in the recent work of Jessica Benjamin and Judith Butler. The field of application is their response to Israel’s treatment of the Palestinians, given their position as Jews. The challenge of the acknowledgement agenda leads back to an issue of general concern – the degree to which relational ethics can prise open apparently closed and defensive psychosocial identities
The effect of exogenous glucose infusion on early embryonic development in lactating dairy cows
peer-reviewedThe objective of this study was to examine the effect of intravenous infusion of glucose on early embryonic development in lactating dairy cows. Nonpregnant, lactating dairy cows (n = 12) were enrolled in the study (276 ± 17 d in milk). On d 7 after a synchronized estrus, cows were randomly assigned to receive an intravenous infusion of either 750 g/d of exogenous glucose (GLUC; 78 mL/h of 40% glucose wt/vol) or saline (CTRL; 78 mL/h of 0.9% saline solution). The infusion period lasted 7 d and cows were confined to metabolism stalls for the duration of the study. Coincident with the commencement of the infusion on d 7 after estrus, 15 in vitro-produced grade 1 blastocysts were transferred into the uterine horn ipsilateral to the corpus luteum. All animals were slaughtered on d 14 to recover conceptuses, uterine fluid, and endometrial tissue. Glucose infusion increased circulating glucose concentrations (4.70 ± 0.12 vs. 4.15 ± 0.12 mmol/L) but did not affect milk production or dry matter intake. Circulating β-hydroxybutyrate concentrations were decreased (0.51 ± 0.01 vs. 0.70 ± 0.01 mmol/L for GLUC vs. CTRL, respectively) but plasma fatty acids, progesterone, and insulin concentrations were unaffected by treatment. Treatment did not affect either uterine lumen fluid glucose concentration or the mRNA abundance of specific glucose transporters in the endometrium. Mean conceptus length, width, and area on d 14 were reduced in the GLUC treatment compared with the CTRL treatment. A greater proportion of embryos in the CTRL group had elongated to all length cut-off measurements between 11 and 20 mm (measured in 1-mm increments) compared with the GLUC treatment. In conclusion, infusion of glucose into lactating dairy cows from d 7 to d 14 post-estrus during the critical period of conceptus elongation had an adverse impact on early embryonic development
Turning back
This response to Miri Rozmarin’s paper, Staying Alive, focuses on the question of what it might mean to create a response to matricide and patriarchal violence that is grounded in the particularities of cultural and personal history. Rozmarin’s rendering of a possible response to matricide through the mother-daughter genealogy is illustrated in her analysis of the Biblical myth of Lot’s wife. She claims that this story of destruction, punishment and incest reveals ‘an option of non-matricidal relations’ and she gives a compelling account of how this could be so. In my response, I suggest that there are alternative ‘against the grain’ readings that are grounded in the Jewish traditions and sensibilities in which such ‘mythic’ material is embedded and from which it draws its vitality. I offer an example of this, not to refute Rozmarin’s claims, but to suggest that something more nuanced and even loving can be found in the specificity of this cultured and gendered encounter, and that this better meets the conditions for ‘concrete’ ethical resistance that she seeks
Characterization of anogenital distance and its relationship to fertility in lactating Holstein cows
peer-reviewedAnogenital distance (AGD) serves as a marker for prenatal androgenization, reproductive development, and fertility in humans and rodents. The primary objectives of this observational study in lactating dairy cows were to (1) characterize the distribution and variability of AGD, (2) determine the relationship among AGD and potential postnatal AGD determinants of age and height, and (3) evaluate the associations between AGD and pregnancy to first artificial insemination (P/AI) and cumulative pregnancy by 250 d in milk (DIM) within parity groups (first, second, and third+ parities). The secondary objective was to evaluate the association between AGD and testosterone concentrations. The AGD (mm), age (yr), and height at hip (cm) at the time of AGD determination, and aforesaid reproductive outcomes were determined in 921 Holstein cows (first, second, and third+ parity; n = 360, 256, and 305, respectively). Plasma concentrations of testosterone were determined in a subset of 93 cows. Overall, AGD had a normal distribution and high variability [mean (±standard deviation); 131.0 ± 12.2 mm], was weakly associated with cow age and height (coefficient of determination = 0.09 and 0.04, respectively), and had an inverse relationship with P/AI in first- and second-parity cows, but not in third+ parity cows. For every 1 mm increase in AGD, the odds of P/AI decreased by 3.4 and 2.4% for first- and second-parity cows, respectively. The optimal AGD threshold to predict probability of P/AI was 127.1 mm for both first- (sensitivity: 66.4; specificity: 56.6%) and second-parity cows (sensitivity: 46.0; specificity: 70.4%). Accordingly, first- and second-parity cows were categorized into either short or long AGD (≤ or >127.1 mm), and associations with reproductive outcomes were evaluated. First-parity cows with long AGD had lower P/AI (30.9 vs. 53.6%) and decreased likelihood (hazard ratio: 0.68) of pregnancy by 250 DIM than those with short AGD. Similarly, second-parity cows with long AGD had reduced P/AI (28.3 vs. 44.4%) and a tendency for decreased likelihood (hazard ratio: 0.76) of pregnancy by 250 DIM than in cows with short AGD. The association between AGD and testosterone was weak and nonsignificant. In summary, AGD in Holstein cows was normally distributed, highly variable, and weakly associated with age and height. Besides, AGD had an inverse relationship with P/AI and cumulative pregnancy by 250 DIM in first- and second-parity cows; however, such a relationship was not evident in older (third+ parity) cows.This project was financially supported in part by Growing Forward 2, a federal-provincial-territorial initiative (Research Opportunities and Innovation–Internal Initiatives Project # DA7642064). M. Gobikrushanth is a recipient of the Teagasc-University of Alberta Walsh Fellowship sponsored by Alberta Innovates Biosolutions
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