3,999 research outputs found
Integration of technologies for understanding the functional relationship between reef habitat and fish growth and production
Functional linkage between reef habitat quality and fish growth and production has remained elusive. Most current research is focused on correlative relationships between a general habitat type and presence/absence of a species,
an index of species abundance, or species diversity. Such descriptive information largely ignores how reef attributes
regulate reef fish abundance (density-dependent habitat selection), trophic interactions, and physiological performance (growth and condition). To determine the
functional relationship between habitat quality, fish abundance, trophic interactions, and physiological performance, we are using an experimental reef system in
the northeastern Gulf of Mexico where we apply advanced sensor and biochemical technologies. Our study site controls for reef attributes (size, cavity space, and reef
mosaics) and focuses on the processes that regulate gag grouper (Mycteroperca microlepis) abundance, behavior and performance (growth and condition), and the availability of their pelagic prey. We combine mobile and fixed-active (fisheries) acoustics, passive acoustics, video cameras,
and advanced biochemical techniques. Fisheries acoustics quantifies the abundance of pelagic prey fishes associated
with the reefs and their behavior. Passive acoustics and video allow direct observation of gag and prey fish behavior and the acoustic environment, and provide a
direct visual for the interpretation of fixed fisheries acoustics measurements. New application of biochemical techniques, such as Electron Transport System (ETS) assay,
allow the in situ measurement of metabolic expenditure of gag and relates this back to reef attributes, gag behavior, and prey fish availability. Here, we provide an overview of our integrated technological approach for understanding and quantifying the functional relationship between reef habitat quality and one element of production ā gag grouper growth on shallow coastal reefs
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 āacknowledgement-basedā relational ethics in the recent work of Jessica Benjamin and Judith Butler. The field of application is their response to Israelās treatment of the Palestinians, given their position as Jews. The challenge of the acknowledgement agenda leads back to an issue of general concern ā the degree to which relational ethics can prise open apparently closed and defensive psychosocial identities
The effect of strategic supplementation with trans-10,cis-12 conjugated linoleic acid on the milk production, estrous cycle characteristics, and reproductive performance of lactating dairy cattle
Peer-reviewedThis is the authorās version of a work that was accepted for publication in Journal of Dairy Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Dairy Science, Volume 95, Issue 5, May 2012, Pages 2442-2451: DOI 10.3168/jds.2011-4632The objective was to determine the effects of a protected (lipid-encapsulated) conjugated linoleic acid (LE-CLA) supplement on milk production, estrous cycle characteristics, and reproductive performance in lactating dairy cows on a pasture-based diet. Spring calving dairy cows (n = 409) on a single pasture-based commercial dairy farm were used in a completely randomized block design. Cows were assigned to 1 of 2 dietary supplements [LE-CLA (n = 203) or no supplement (control, n = 206)]. The LE-CLA cows received 51 g/d of a lipid supplement containing 5 g of both trans-10,cis-12 and cis-9,trans-11 CLA from 0 to 60 d in milk. Milk samples were collected 3 times weekly, and each sample was analyzed for progesterone to determine the interval to first ovulation and estrous cycle characteristics. Milk yield and concentrations of fat, protein, and lactose were measured every 2 wk. Cows were inseminated following visual observation of estrus. The breeding season commenced on April 8, 2009 and continued for 16 wk. Transrectal ultrasonography was carried out at 30 to 36 d and 60 to 66 d post-AI to diagnose pregnancy. The LE-CLA treatment resulted in a decrease in milk fat concentration (36.9 Ā± 0.06 g/kg vs. 30.7 Ā± 0.06 g/kg for control and LE-CLA, respectively) and yield (0.91 Ā± 0.02 kg/d vs. 0.84 Ā± 0.02 kg/d for control and LE-CLA, respectively); however, milk yield was increased by LE-CLA supplementation (24.7 Ā± 0.7 kg/d vs. 27.2 Ā± 0.7 kg/d for control and LE-CLA, respectively), resulting in no overall difference in milk energy output. No effect of LE-CLA was observed on any estrous cycle characteristics or measures of reproductive performance. These results support that in pasture-based systems of dairy production, where energy intake limits milk production, energy spared by CLA-induced milk fat depression is partitioned toward increasing milk yield rather than toward body reserves
Effect of supplementation with different fat sources on the mechanisms involved in reproductive performance in lactating dairy cattle
peer reviewedSupplementary fat positively influences reproductive performance in dairy cattle, although the mechanisms involved are not clearly defined. Our objective was to determine the effects of four different fat supplements on follicle development, plasma steroid hormone concentrations and prostaglandin (PG) synthesis in lactating dairy cattle. Forty-eight early lactation Holstein-Friesian cows (21 primiparous, 27 multiparous) were used in a completely randomized block design. Cows were fed the same basal TMR diet and received one of four fat supplements: (i) palmitic acid (18:0 fatty acid; Control), (ii) flaxseed (rich in 18:3 n-3 fatty acid; Flax), (iii) conjugated linoleic acid (a mixture of cis-9, trans-11 and trans-10, cis-12 isomers; CLA), and (iv) fish oil (rich in 20:5 and 22:6 n-3 fatty acids; FO). All lipid supplements were formulated to be isolipidic; palmitic acid was added as necessary to provide a total lipid supplement intake of 500 g/day. Cows were synchronized to be in estrus on Day 15 of dietary treatment. All antral follicles were counted, and dominant follicles, subordinate follicles and corpora lutea were measured daily via transrectal ovarian ultrasonography for one complete estrous cycle. Blood samples were collected daily, and selected samples were analyzed for progesterone, estradiol, insulin-like growth factor-1, insulin, cholesterol and non-esterified fatty acids. Estrus was synchronized a second time, and liver and endometrial biopsies were collected on Day 7 of the estrous cycle. Gene expression was evaluated for a number of genes involved in prostaglandin synthesis (endometrium) and fatty acid uptake and utilization (liver). Fat supplementation had little effect on follicle development. Cows receiving supplementary n-3 fatty acids had lesser plasma progesterone (P4) and smaller corpora lutea than cows receiving the CLA or Control supplements. Effects of fat supplementation on the endometrial expression of genes involved in PG synthesis were minor. Hepatic expression of SREBF1, ASCL1 and FABP1 was reduced by FO supplementation. Reduced plasma P4 in n-3 supplemented cows may lead to a suboptimal uterine environment for embryo development and hence reduced fertility compared to cows receiving the control or CLA supplements
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
Beyond recognition: the politics of encounter
The context for this paper is an attempt to think through the possibilities and challenges of nonviolent resistance, with the shadow of the Israel-Palestine conflict looming over it. Drawing on the work of Jessica Benjamin, I outline how a theory of recognition becomes one of acknowledgement through the inclusion of a notion of a witnessing āthirdā. This third is actively implicated in the injury caused by oppression and is called upon to do something about it. I go on to use Judith Butlerās account of the challenge of nonviolence to draw out some lessons on issues of vulnerability, cohabitation and justice. Finally, I return to the question of the kind of witnessing third that might make a difference
Turning back
This response to Miri Rozmarinās 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. Rozmarinās rendering of a possible response to matricide through the mother-daughter genealogy is illustrated in her analysis of the Biblical myth of Lotās wife. She claims that this story of destruction, punishment and incest reveals āan option of non-matricidal relationsā and she gives a compelling account of how this could be so. In my response, I suggest that there are alternative āagainst the grainā readings that are grounded in the Jewish traditions and sensibilities in which such āmythicā material is embedded and from which it draws its vitality. I offer an example of this, not to refute Rozmarinās 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 āconcreteā ethical resistance that she seeks
Geikie's field researches and their geological controversies
All of us were introduced to the Moine Thrust Belt and its controversies by the late Mike Coward. We are indebted to him for instilling a passion for structural geology, challenging conventional wisdom and for tales of early protagonists. We also thank the late John Mendum, who kindly shared a copy of his notes on the Highlands Controversy, together with Robert Neller, Collections Officer at Haslemere Educational Museum, for facilitating access to Geikieās field-notes and artwork.Peer reviewedPostprin
Strain and Magnetic Fabric in Santa Catalina and Pinaleno Mountains Metamorphic- Core-Complexes Mylonite Zones, Arizona
Anisotropy of magnetic susceptibility (AMS) is capable of recording finite strain in weakly magnetized rocks. AMS was measured for 228 samples from 20 sites in two mylonite zones with the same deformational history. AMS measurements were compared with finite strains determined from dike rotations and from foliation orientations. In one zone (the Santa Catalina Mountains) the orientations of susceptibility and finite strain ellipsoids are in excellent agreement, and there is a logarithmic relationship between susceptibility difference (ĪKi = [Ki-K]/K) and finite strain magnitude. In the second zone (the Pinaleno Mountains) minimum susceptibility is perpendicular to the finite flattening plane, but the maximum susceptibility does not parallel the maximum extension direction, and there is no systematic relationship between susceptibility magnitude and strain magnitude. Oriented polished thin sections indicate that magnetite in the protolith of the Santa Catalina mylonite occurs as randomly oriented, elongate grains. With subsequent deformation, the long axes are rotated into the maximum extension direction. In the Pinaleno mylonites, both equant and elongate magnetite grains are present. With deformation, the elongate magnetite grains are rotated into the maximum flattening plane but show no preferred orientation within this plane. AMS in the two mylonite zones appears to be predominantly controlled by the orientation of elongate magnetite grains with respect to the megascopic fabric. The final orientation of the elongate grains is a function of their initial orientation as well as the finite strain. Therefore, despite similar deformational histories, the two zones display different AMS patterns due to the differences in occurrence, initial orientation, and shape of ferromagnetic grains
The social geography of childcare: 'making up' the middle class child
Childcare is a condensate of disparate social forces and social processes. It is gendered and classed. It is subject to an excess of policy and political discourse. It is increasingly a focus for commercial exploitation. This is a paper reporting on work in progress in an ESRC funded research project (R000239232) on the choice and provision of pre-school childcare by middle class (service class) families in two contrasting London locations. Drawing on recent work in class analysis the paper examines the relationships between childcare choice, middle class fractions and locality. It suggests that on the evidence of the findings to date, there is some evidence of systematic differences between fractions in terms of values, perspectives and preferences for childcare, but a more powerful case for intra-class similarities, particularly when it comes to putting preferences into practice in the 'making up of a middle class child' through care and education
- ā¦