DIVERSIFICATION OF REGIONAL MARKETING COOPERATIVES

Agribusiness, Marketing,

Connections of the Mesencephalic Locomotor Region (MLR) in the Cat

The cat entopeduncular nucleus (EN), which is the main output of the basal ganglia, is known to project to the mesencephalic tegmentum. We have been able to elicit antidromic responses in single EN neurons from the region of the mesencephalic locomotor region (MLR), then transect (precollicular-postmamillary) the brainstem and elicit rhythmic movements of the limbs by stimulation of the same site in the same animal. Injections of the fluorescent dye 2,4 diamidino phenylindole 2 HCL (DAPI) into this area induces retrograde labeling of cell bodies in EN and motor cortex. Injections of a tritiated amino acid (leucine) into the motor cortex induce terminal labeling in the area of the MLR. These studies describe convergent projections from EN and motor cortex to the MLR. These connections may be involved in the sequencing and ordering of voluntary movements in which locomotion is necessary

Struggles on the page:British Antiapartheid and Radical Scholarship

This article combines an overview of the historiography of antiapartheid movements with a case study of radical scholarship on South Africa in the 1960s. It highlights the ways that antiapartheid activism effectively framed public understanding of the idea of apartheid and its application in South Africa. Using the British African solidarity movement as an example, it addresses the mutually constitutive relationship between the antiapartheid movement and radical analyses of South African politics and society. From the emergence of international responses to apartheid that began in the 1950s, activist research was at the leading edge of organized opposition to South African government policies and a transnational influence on radical politics in Britain.</jats:p

SUPPLY RESPONSE UNDER THE 1996 FARM ACT AND IMPLICATIONS FOR THE U.S. FIELD CROPS SECTOR

The 1996 Farm Act gives farmers almost complete planting flexibility, allowing producers to respond to price changes to a greater extent than they had under previous legislation. This study measures supply responsiveness for major field crops to changes in their own prices and in prices for competing crops and indicates significant increases in responsiveness. Relative to 1986-90, the percentage increases in the responsiveness of U.S. plantings of major field crops to a 1-percent change in their own prices are wheat (1.2 percent), corn (41.6 percent), soybeans (13.5 percent), and cotton (7.9 percent). In percentage terms, the increases in the responsiveness generally become greater with respect to competing crops' price changes. The 1996 legislation has the least effect on U.S. wheat acreage, whereas the law may lead to an average increase of 2 million acres during 1996-2005 in soybean acreage, a decline of 1-2 million acres in corn acreage, and an increase of 0.7 million acres in cotton acreage. Overall, the effect of the farm legislation on regional production patterns of major field crops appears to be modest. Corn acreage expansion in the Central and Northern Plains, a long-term trend in this important wheat production region, will slow under the 1996 legislation, while soybean acreage expansion in this region will accelerate. The authors used the Policy Analysis System-Economic Research Service (POLYSYS-ERS) model that was jointly developed by USDA's Economic Research Service and the University of Tennessee's Agricultural Policy Analysis Center to estimate the effects of the 1996 legislation.Supply response, major field crops, acreage price elasticities, normal flex acreage (NFA), 1996 farm legislation., Agricultural and Food Policy, Crop Production/Industries,

Development of a Multidimensional, Multi-Informent Measure of Teacher Mindfulness as Experienced and Expressed in the Middle School Classroom

In response to growing interest in mindfulness as a support for educators, the current study sought to create and test a new multidimensional and multi-informant measure of teacher mindfulness in the classroom. To counter some of the limitations of context-general self-reports, we designed two theoretically based classroom-specific measures that capture the experience and expression of mindful teacher behavior from the perspective of teachers and students. Drawing on emerging consensus from experts on mindfulness in education, the measures incorporated three dimensions of mindfulness, namely, Calm, Clear, and Kind teacher behavior in the classroom, as well as their antitheses, namely, Reactive, Distracted, and Critical teacher behavior. Utilizing data from 78 sixth- to eighth-grade teachers and 550 of their students, teacher- and student-report item sets tapping these dimensions were tested for reliability and validity across three time points. Based on confirmatory factor, reliability, structural invariance, and correlational analyses, subscales generally demonstrated satisfactory psychometric properties, cross-year stabilities, convergent and criterion validity with multiple established measures, and some overlap across reporters. In terms of connections to observer ratings from the CLASS-S, teacher subscales showed consistent but modest connections, whereas student subscales showed higher correlations (especially at time 2), suggesting that students and observers converged in their perceptions of teachers’ expressions of mindfulness. Possible improvements to both measures as well as implications for future research on teacher mindfulness are discussed

Material Loss at the Head Taper Junction of the Metal-on-Metal Pinnacle Total Hip Replacement

Introduction The ASR XL (DePuy) total hip replacement (THR) is a notable example of a modern metal-on-metal (MOM) implant design that has demonstrated unacceptable survival rates, leading to its recall by the manufacturer; national joint registries have reported revision rates at 7 years of 40% when paired with the Corail stem [1]. The ASR XL THR has a considerably greater risk of revision than the ASR resurfacing hip, which used the same bearing design. This suggests that material loss at the head-stem junction may be responsible for the greater percentage of THR failures observed in this design. The Pinnacle MOM-THR (DePuy) however used the same Corail stem as the ASR XL THR but demonstrated better clinical results, with revision rates of less than 10% at 7 years [1]. The ASR XL and MOM Pinnacle are two designs that have been widely used in hip replacement surgery. The reasons for the differences in the failure rates of the two designs are not fully understood. Comparing the mechanisms of failure of both hips will help surgeons understand whether patients with MOM Pinnacle hips will experience the same types of problems as with those seen with the ASR XL. The aims of this retrieval study were to investigate the significance of differences between the ASR XL and MOM Pinnacle in relation to: (1) pre-revision whole blood Co/Cr ratios, (2) visual evidence of taper corrosion, (3) volumetric material loss at the bearing surfaces and (4) volumetric material loss at the taper surfaces. Methods This study involved a series of failed MOM hips consisting of the ASR XL (n=30) and Pinnacle (n=30), all that had been used with a Corail stem. The bearing material in each design was cobalt-chromium and the Corail stem is of a cementless titanium 12/14 design. The ASR XL and Pinnacle had a median head diameter of 47mm (39-55) and 36mm (36-40) respectively, and a median time to revision of 38.5 months (12-74) and 55 months (14-86) respectively. Pre-revision whole blood metal ion levels were collected for each Table 1 summarises patient and implant data for the hips in this study. The female taper surfaces of all 60 heads were examined macroscopically and microscopically to assess the severity of corrosion. Each surface was graded with a score of between 1 (no corrosion) and 4 (severe corrosion) using a well-published scoring system, which has been shown to be statistically reliable. A Zeiss Prismo (Carl Zeiss Ltd, Rugby, UK) coordinate measuring machine (CMM) was used to determine the volume of material loss at the cup and head bearing surfaces. Up to 300,000 data points were collected using a 2mm ruby stylus that was translated along 400 polar scan lines on the surface. The raw data was used to map regions of material loss by comparing with the unworn geometry of the bearing. A Talyrond 365 (Hobson, Leicester, UK) roundness measuring machine was used to measure the volumetric material loss at each of the head taper surfaces. Published protocols were used to take a series of 180 vertical traces along the taper surface using a 5μm diamond stylus; worn and unworn regions were mapped and used to calculate material loss. Neither the volumetric measurement data nor corrosion scores were normally distributed. Therefore non-parametric tests were performed to assess the statistical significance of differences between the two designs in relation to the parameters under investigation in this study. Results Both the whole blood Co ion levels and the Co/Cr ratios, Figure 1, of the ASR XL hips were significantly greater than the Pinnacles (p<0.05). There was no significant difference between the whole blood Cr ion levels between the two designs (p=0.0542). 18 of the ASR XL hips presented evidence of edge wearing of the cup, compared with 14 Pinnacle hips; this difference was not significant (p=0.438). The length of the stem trunnion contact engagement length with the taper was approximated as being 10.5mm for both designs. The median time to revision of the ASR XL hips was significantly less than the Pinnacle hips (p<0.01). There was visual evidence of corrosion in 93% (n=28) and 90% (n=27) of head tapers for the ASR XLs and Pinnacles respectively. Moderate to severe corrosion was observed in 67% (n=20) of ASR XLs compared to 60% (n=18) of Pinnacles. There was however no statistically significant difference between the scores of the two groups (p=0.927). Figure 2 presents the distribution of material loss rates for the bearing and taper surfaces of the two designs in this study. The median total bearing surface (combined cup and head) rate of material loss for the ASR XL and Pinnacle hips was 4.45mm3/year (0.32-22.85) and 4.03mm3/year (0.87-62.12) respectively. There was no significant difference between the two groups (p=0.928). The median material loss rate at the taper surfaces of the ASR XL and Pinnacle hips was 0.62mm3/year (0-4.20) and 0.30mm3/year (0-3.12); this difference was not significant (p=0.198). Discussion The work of this study presents comparisons of retrieval findings between the ASR XL and Pinnacle MOM-THRs; these hip designs were two of the most commonly implanted in patients worldwide. The significantly greater whole blood Co/Cr ratios found in the ASR XL group compared to the Pinnacle group are of interest. It is speculated that a Co/Cr ratio of greater than 1 may be an indicator of corrosion of an implant whereby more Cr ions are retained on the surface, whilst comparatively more Co ions are released into the blood. In the current study we found wear rates at the bearing surfaces of both designs to be comparable, suggesting that the significantly greater Co/Cr ratios in the ASR XL hips must be due to greater corrosion at the taper junction than the Pinnacles. Although the ASR XL hips had been implanted for a significantly shorter period of time, our visual assessment of the corrosion of the taper junctions found that corrosion scores were comparable between the two designs; indeed, a marginally greater number of ASR XL tapers had evidence of moderate to severe corrosion. This finding, coupled with the elevated Co/Cr ratios suggests that the ASR XL design is more susceptible to corrosion at the taper junction than the Pinnacle hip. We found that the median rate of material loss at the ASR XL taper was over twice that of the Pinnacle taper. Whilst not statistically significant, this difference may be due to a greater risk of corrosion at this interface in the ASR XL design. The differences in material loss and corrosion that were observed at the taper junctions may be explained by considering the larger head sizes of the ASR XL hips in comparison to the Pinnacles. It has previously been shown that increasing head size is correlated with greater visual evidence of corrosion and that increased frictional torque along the taper junction due a larger head diameter can increase the risk of fretting-corrosion. It is suggested therefore that the combination of the larger head sizes of the ASR XLs coupled with the comparatively short, rough surface of the Corail trunnion results in a cumulative effect leading to greater corrosion at the taper junction. Significance The results of the study suggest that the combination of (1) increased frictional torque in the larger ASR XLs and (2) the rough Corail trunnion surface, results in greater corrosion at the taper junction in comparison to the Pinnacle hips; this helps to explain the higher risk of revision in this hip design

Identifying The Pattern of Material Loss at the Head-Neck Junction Wear Helps Determine the Mechanism of Failure of Metal on Metal Total Hip Replacements

Material loss at the Head-Neck junction accounts for a third of the total volume material loss in contemporary metal-on-metal total hip replacements. It is speculated that the material loss is the result of corrosion and mechanical wear (fretting). High volumes of material loss have been reported, especially from the head taper. There is only one report on characterizing the pattern of material loss and this was in a very small number of cases (n=5). Our aim was to identify the different material loss patterns at the head taper and their corresponding mechanisms We retrospectively analysed a series of retrieved Large Head Metal on Metal Total Hip Replacements (155 cups, 155 femoral heads and 4 stems). We measured material loss on the bearing surfaces and the head-neck junction using well-published metrology methods. Furthermore we collected patient (age, gender and time of primary/revision operations), pre-revision (cobalt and chromium blood metal ion, oxford hip score, cup orientation and implant position) implant (cup and head size, manufacturer and corrosion severity) data. Finally we used surface analysis techniques (microscopy and spectroscopy) to identify fretting, imprinting and the material composition of debris. We devised a novel four-group classification and two blinded engineers classified the material loss patterns using wear maps derived from the metrology analysis We observed four distinct patterns of taper surface material loss at our retrieval centre and we set out to characterize these types and relate them to patient, implant and clinical variables. The four groups of material loss patterns were defined as: (1) Low wear (n= 63), (2) Open-end band (n=32), (3) Stripped material loss (n=54) and (4) Coup-Countercoup (n=6) (Figure). The Interobserver Reliability Kappa score was 0.78 (p<0.001) indicating substantial agreement between the two examiners. Analysis of variables between the groups identified significantly different head sizes (highest: Group 2, p=0.000), corrosion severity (highest: Group 2, p=0.004) and time to revision (highest: Group 3, p=0.040). We identified four different material loss patterns each with its own mechanism. Corrosion was identified as the principal mechanism in Groups 1 and 3. Group 1 head-neck junctions are thought to have a better seal with less fluid ingress in the junction. Group 3 head-neck junctions are attacked by corrosion either circumferentially, or unilaterally, along the whole engagement length. Mechanically assisted corrosion was the principal mechanism in Group 2. The higher friction torque opens up the open-end part of the junction and the ingressing fluid accelerates the corrosion. Extensive fretting was also observed under the scanning electron microscope. Intra-operative surgical damage was identified as the principal mechanism in Group 4, with only 6 components. The patterns and the mechanisms of material loss at the head-neck junction contribute to the understanding of large head metal-on-metal hip replacements. As a result, better implants can be designed in the future. Clinically, these findings suggest that head size and head taper-trunnion fit are the main factors that determine the longevity of the head-neck junction. On the other hand, patients selection does not influence the integrity of the junction

ABERRANT TESTA SHAPE encodes a KANADI family member, linking polarity determination to separation and growth of Arabidopsis ovule integuments

The Arabidopsis aberrant testa shape (ats) mutant produces a single integument instead of the two integuments seen in wild-type ovules. Cellular anatomy and patterns of marker gene expression indicate that the single integument results from congenital fusion of the two integuments of the wild type. Isolation of the ATS locus showed it to encode a member of the KANADI (KAN) family of putative transcription factors, previously referred to as KAN4. ATS was expressed at the border between the two integuments at the time of their initiation, with expression later confined to the abaxial layer of the inner integument. In an inner no outer (ino) mutant background, where an outer integument does not form, the ats mutation led to amorphous inner integument growth. The kan1 kan2 double mutant exhibits a similar amorphous growth of the outer integument without affecting inner integument growth. We hypothesize that ATS and KAN1/KAN2 play similar roles in the specification of polarity in the inner and outer integuments, respectively, that parallel the known roles of KAN proteins in promoting abaxial identity during leaf development. INO and other members of the YABBY gene family have been hypothesized to have similar parallel roles in outer integument and leaf development. Together, these two hypotheses lead us to propose a model for normal integument growth that also explains the described mutant phenotypes

X-raying the Beating Heart of a Newborn Star: Rotational Modulation of High-energy Radiation from V1647 Ori

We report a periodicity of ~1 day in the highly elevated X-ray emission from the protostar V1647 Ori during its two recent multiple-year outbursts of mass accretion. This periodicity is indicative of protostellar rotation at near-breakup speed. Modeling of the phased X-ray light curve indicates the high-temperature (~50 MK), X-ray-emitting plasma, which is most likely heated by accretion-induced magnetic reconnection, resides in dense (>~5e10 cm-3), pancake-shaped magnetic footprints where the accretion stream feeds the newborn star. The sustained X-ray periodicity of V1647 Ori demonstrates that such protostellar magnetospheric accretion configurations can be stable over timescales of years.Comment: 26 pages, 10 figure