A rat model for orthodontic translational expansive tooth movement

OBJECTIVES To present the development of an experimental model in rats for translational expansive tooth movement. SETTING AND SAMPLE Section of Periodontology at Department of Dentistry Aarhus University. Twenty male Wistar rats in two pilot experimental settings plus seven animals without any intervention serving as controls. MATERIAL AND METHODS The second molar (group P1) or the second and third molar (group P2) in the maxillae of the animals were moved buccally using transpalatal β-titanium springs. In the group P2, two spring types (high force and low force) and two preangulations (0° passive or 30° torsion moment) were tested. The amount and type of tooth movement achieved and the resulting skeletal effect were assessed on microCT images, histological analysis was performed on few selected specimens. RESULTS Expansive translational root movement amounting half a tooth width was achieved. Comparison of the amount of tooth movement at the right and left side of the maxilla showed that the expansion was rather symmetrical in the P2 group. Skeletal widening of the maxilla contributed in the P2 group to approximately one-third of the total root movement, whereas two-thirds were dental movement. CONCLUSION With the model used in the P2 group, further research on translational expansive tooth movement and its effect on the periodontium can be pursued. In models for orthodontic expansion, it is strongly recommended to separately evaluate skeletal and dental effects.

Intensive Rotational Grazing of Steers at the Andrew Jackson Demonstration Farm

Fifty head of crossbred steers started grazing 51 acres of pasture on May 1 in a rotational grazing system using a variable density paddock system. Twenty-two head grazed 92 days, 27 grazed 140 days, and one steer died. A total of 11,922 pounds was produced on 5,804 animal-days of grazing. The average daily gain was 2.02 pounds for group 1 and 2.07 for group 2. The stocking rate for the first 92 days was .98 steers per acre and .53 for the final 48 days. The animal days of grazing per acre was 113 and the pounds of gain per acre was 233. Total return for land, labor and management for the demonstration was $2,829.76 or $55.49/acre.

Evaluation of Hay-Type and Grazing Tolerant Alfalfa Hybrids in Season-Long or Complementary Rotational Stocking Systems for Beef Cows

Pastures containing hay-type and grazing tolerant alfalfa hybrids were grazed in a season-long or complementary rotational stocking system with Nfertilized smooth bromegrass. The pastures were stocked at a seasonal density of .8 cow-calf pairs per acre for 120 days in 1998 and 141 days in 1999. Pastures were intensively managed by daily stripstocking with the assumptions that 50% of live forage was available and daily live dry matter consumption of each cow-calf pair was 3.5% of the cow’s body weight. First-cutting forage was harvested as hay from 40% of the pasture acres to remove excess forage growth early in the grazing season. Grazing occurred on the remaining 60% of each pasture for the first 44 and 54 days and 100% of each pasture after days 45 and 55 in 1998 and 1999, respectively. Proportions of ‘Amerigraze’ and ‘Affinity’ alfalfa in the live forage dry matter decreased by 70% and 55% in pastures stocked season-long and by 60% and 42% in pastures used for complementary stocking (alfalfa type, p<.05; grazing management, p<.05) in 1998, but decreased by a mean of 72% and was unaffected by hybrid or stocking system in 1999. Cows grazing either alfalfa hybrid by either grazing system had greater weight gains during the breeding and overall grazing seasons and greater increases in body condition score pre-breeding and during the breeding season than the cows that grazed smooth bromegrass for the entire season in 1998. Also, cows grazing either alfalfa hybrid in the season-long system had greater breeding season increases in body condition score than cows grazing alfalfa in the complementary system with smooth bromegrass in 1998. Cows grazing in the season-long alfalfa system had greater prebreeding season weight (p<.10) increases and condition score (p<.05) increases than cows grazing alfalfa in the complementary system in 1999. Daily and seasonal body weight gains of calves were not affected (p>.10) by the presence of alfalfa in 1998 or by alfalfa type and grazing management in 1998 and 1999. Total animal production (cow and calf) in 1998 was greater (p<.10) from the season-long alfalfa pastures compared with the complementary stocked pastures. Total (p<.10) and live (p<.05) forage masses, estimated by monthly clippings, were greater in September of 1998 from the season-long alfalfa pastures than pastures using alfalfa for complementary stocking. Total (p<.10) and live (p<.05) forage masses were greater in August of 1999 from season-long alfalfa pastures than pastures using alfalfa for complementary stocking.

Evaluation of Hay-Type and Grazing Tolerant Alfalfa Hybrids in Season-Long or Complementary Rotational Stocking Systems for Beef Cows

Pastures containing hay-type and grazing tolerant alfalfa hybrids were grazed in a season-long or complimentary rotational stocking system with Nfertilized smooth bromegrass. The pastures were stocked at a seasonal density of .8 cow-calf pairs per acre for 120 days. Pastures were intensively managed by daily strip-stocking with the assumptions that 50% of live forage was available and daily live dry matter consumption of each cow-calf pair was 3.5% of the cow’s body weight. First-cutting forage was harvested as hay from 40% of pasture acres to remove excess forage growth early in the grazing season. Forage was grazed from the remaining 60% of each pasture for the first 44 days of the experiment and then from the entire pasture thereafter. Live forage yields, estimated by monthly clippings, were greater in May and September on the season-long alfalfa pastures compared with the complementary pastures and on the alfalfa pastures compared with the N-fertilized smooth bromegrass pastures. The proportions of legumes in the live dry matter in pastures with grazing tolerant and hay-type alfalfas in the season-long grazing systems declined by 70% and 50%, respectively, in the 120 day trial. The proportions of legumes in the live dry matter in pastures with grazing tolerant and the hay-type alfalfas in the complementary grazing system declined 60% and 42%, respectively, in the 120 day trial. Cows grazing either alfalfa hybrid by either management system had greater weight gains during the breeding and grazing seasons and greater increases in body condition score prebreeding and during the breeding season than the cows that grazed N-fertilized smooth bromegrass for the entire season. Also, cows grazing either alfalfa in the season-long system had greater breeding season increases in body condition score than cows grazing alfalfa in the complementary system with N-fertilized smooth bromegrass. Daily gains and seasonal gains of calves from cows grazing the alfalfa pastures tended to be greater than those grazing N-fertilized smooth bromegrass. Within alfalfa treatments, calves of cows grazing alfalfa pastures in the season-long system tended to produce more pounds per acre than those of cows grazing alfalfa in the complementary systems.

Alternative Rotational Grazing Systems at the Beef Teaching Farm

Fifty-six acres of central Iowa corn land were seeded to bromegrass and divided with high-tensile wire into eight seven-acre plots. This bromegrass was fertilized with 70 pounds of nitrogen each spring and fall, 1987-1990. In 1991 – 1995, the nitrogen was increased to 80 pounds both spring and fall. The plots were stocked with 1.3 cow/calf pairs per acre in 1987-1991 and 1993–1995, but in 1992 the plots were stocked with 1.55 cow/calf pairs per acre. The pairs were rotated using two distinct schemes among four cells for about 150 days. The plots averaged 607 pounds of net calf weight per acre per year over nine years. Rainfall was quite variable during the grazing seasons and was reflected in calf performance as well as summer feed costs. This intensive rotational grazing system has greatly reduced both weed population and the need for mechanical clipping.

An Economic Comparison of Rotational Grazing Systems to Eight Crop Alternatives and the CRP Option for Highly Erodible Land in Southwest Iowa

Economic comparisons of income on highly erodible land (HEL) in Adams County were made utilizing five years of grazing data collected from a 13- paddock intensive-rotational grazing system and a four-paddock rotational-grazing system and four years of data collected from an 18-paddock intensive-rotational grazing system, all at the Adams County CRP Research and Demonstration Farm near Corning. Net income from the average grazing weight-gain of Angus-sired calves nursing crossbred cows was compared to the net income from grazing yearling steers, to the net income of eight NRCS-recommended crop rotations, and to the Conservation Reserve Program (CRP) option. Results of these comparisons show the 13-paddock intensive rotational grazing system with cow-calf pairs to be the most profitable alternative, with a net return of $19.86 per acre per year. The second most profitable alternative is the CRP option, with a net return of $13.09 per acre, and the third most profitable option is the fourpaddock rotation with cows and calves with a net return of $12.53 per acre. An 18-paddock system returned a net income of $2.47 per acre per year with cows and calves in 1993, but lost an average of $107.69 per acre each year in 1994 and 1995 with yearling steers. Each year, the steers were purchased high and sold low, contributing to the large loss per acre. The following recommended crop rotations all show net losses on these 9-14 % slope, Adair-Shelby Complex soils (ApD3): continuous corn; corn-soybean rotation; corn-soybean rotation with a farm program deficiency payment; corn-corn-corn-oats-meadow-meadow rotation with grass headlands; continuous corn to “T” with grass headlands and buffer strips; continuous corn to “T” with grass headlands, buffer strips, and a deficiency payment; corn-corn-oats-meadow rotation to “T”; and corn-soybeans-oats-meadow-meadow-meadow-meadow rotation to “T”. Per-acre yield assumptions of 90 bushels for corn, 30 bushels for soybeans, 45 bushels for oats, and four tons for alfalfa were used, with per-bushel prices of $2.40 on corn, $5.50 on soybeans, and $1.50 on oats. Alfalfa hay was priced at $40.00 per ton and grass hay at $33.33 per ton. The calf weight-gain in the cow/ calf systems was valued at $.90 per pound. All crop expenses except land costs were calculated from ISU publication Fm 1712, “Estimated Costs of Crop Production in Iowa - 1995.” Land costs were determined by using an opportunity cost and actual property tax figures for the land at the grazing site. In preparation for the end of the CRP beginning in 1996, further economic comparisons will be made after additional grazing seasons and data collection. This project is an interagency cooperative effort sponsored by the Southern Iowa Forage and Livestock Committee which has special permission from the USDA Farm Service Agency (FSA) to use CRP land for research and demonstration.

Intensive Rotational Grazing of Steers on Highly Erodible Land at the Adams County CRP Project

Grazing yearling steers is one way to utilize the forages required for participation in the Conservation Reserve Program (CRP) after CRP contracts expire. In 1995, a stocker-steer intensive-rotational grazing study was conducted at the CRP Research and Demonstration Project near Corning, Iowa. A similar study was carried out in 1994. Seventy-five yearling crossbred steers grazed a 65- acre pasture that had been divided into 27 paddocks using electric fencing from May 4, 1995 to September 14, 1995. During this period, the 65-acre pasture system produced 9,975 animal-days of grazing and 11,403 pounds of gain. On a per-acre basis, this translates to 153.5 animal-days of grazing and 175.4 pounds of gain. The stocking rate was constant for the entire 133- day grazing season at 1.15 steers per acre. On May 4, 1995, the beginning of the grazing season, the average weight of the steers was 495.7 pounds. By the end of the grazing trial on September 14, 1995, the average weight of the steers had increased to 647.7 pounds. The average gain per steer during the 133-day grazing period was 152 pounds, and the average daily gain per steer was 1.14 pounds. The average bodyweight of the steers during the entire grazing season was 571.7 pounds.

Rotational Grazing Demonstrations with Beef Cows on CRP Land in Adams County, 2001

Two rotational-grazing systems, a 13-paddock and a 4-paddock, have been demonstrated on CRP land near Corning, Iowa since 1991 and this report summarizes the 2001 production data. Establishment of this project was to show economically feasible grass alternatives to row crops and CRP for steeply sloping (9% - 14% slope), highly-erodible land (HEL). Stocking rates were 1.57 and 1.72 acres per pair on the 13- and 4-paddock systems, respectively. In a 119 day grazing season calves gained 2.23 and 2.27 lbs/day for the 13- and 4-paddock systems, while cows gained 51.4 and 113.4 lbs, respectively. While some system hay growth was utilized to stave off drought conditions, there was a net hay gain of 11 and 5.5 bales of hay for the 13- and 4-paddock systems, respectively

Intensive Rotational Grazing of Steers on Highly Erodible Land at the Adams County CRP Project, 2001

A steer grazing demonstration was conducted in 2001 at the CRP Research and Demonstration Project farm near Corning, Iowa. Ninety-five steers were delivered to the Adams County CRP farm on April 27, 2001. The steer pasture at the CRP farm was 76 acres, divided into 33 paddocks with electric fence. Cattle were moved 101 times to a fresh paddock during the grazing season. Most of the moves (79.2%) followed 1 day of grazing in a paddock. No paddock was grazed for more than 3 days in succession. Rate of gain on pasture (2.12 lbs./animal/day) was higher in 2001 than in any previous year in the 8-year steer grazing project at the CRP farm. The 95 steers gained a total of 21,056 pounds on pasture, and the cost of the gain on pasture was $51.30/cwt. The 2001 steer grazing project showed a small profit above all costs. The net profit was $4.12/steer or $5.15/acre. Large profits and large losses are possible, primarily depending on the difference between the buying and selling prices.

Rotational integral geometry of tensor valuations

We derive a new rotational Crofton formula for Minkowski tensors. In special cases, this formula gives (1) the rotational average of Minkowski tensors defined on linear subspaces and (2) the functional defined on linear subspaces with rotational average equal to a Minkowski tensor. Earlier results obtained for intrinsic volumes appear now as special cases.

Comfort of two shoulder actuation mechanisms for arm therapy exoskeletons: a comparative study in healthy subjects

Robotic exoskeletons can be used to study and treat patients with neurological impairments. They can guide and support the human limb over a large range of motion, which requires that the movement trajectory of the exoskeleton coincide with the one of the human arm. This is straightforward to achieve for rather simple joints like the elbow, but very challenging for complex joints like the human shoulder, which is comprised by several bones and can exhibit a movement with multiple rotational and translational degrees of freedom. Thus, several research groups have developed different shoulder actuation mechanism. However, there are no experimental studies that directly compare the comfort of two different shoulder actuation mechanisms. In this study, the comfort and the naturalness of the new shoulder actuation mechanism of the ARMin III exoskeleton are compared to a ball-and-socket-type shoulder actuation. The study was conducted in 20 healthy subjects using questionnaires and 3D-motion records to assess comfort and naturalness. The results indicate that the new shoulder actuation is slightly better than a ball-and-socket-type actuation. However, the differences are small, and under the tested conditions, the comfort and the naturalness of the two tested shoulder actuations do not differ a lot.

Saccadic eye movement changes in Parkinson's disease dementia and dementia with Lewy bodies.

Neurodegeneration in Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) affect cortical and subcortical networks involved in saccade generation. We therefore expected impairments in saccade performance in both disorders. In order to improve the pathophysiological understanding and to investigate the usefulness of saccades for differential diagnosis, saccades were tested in age- and education-matched patients with PDD (n = 20) and DLB (n = 20), Alzheimer's disease (n = 22) and Parkinson's disease (n = 24), and controls (n = 24). Reflexive (gap, overlap) and complex saccades (prediction, decision and antisaccade) were tested with electro-oculography. PDD and DLB patients had similar impairment in all tasks (P > 0.05, not significant). Compared with controls, they were impaired in both reflexive saccade execution (gap and overlap latencies, P < 0.0001; gains, P < 0.004) and complex saccade performance (target prediction, P < 0.0001; error decisions, P < 0.003; error antisaccades: P < 0.0001). Patients with Alzheimer's disease were only impaired in complex saccade performance (Alzheimer's disease versus controls, target prediction P < 0.001, error decisions P < 0.0001, error antisaccades P < 0.0001), but not reflexive saccade execution (for all, P > 0.05). Patients with Parkinson's disease had, compared with controls, similar complex saccade performance (for all, P > 0.05) and only minimal impairment in reflexive tasks, i.e. hypometric gain in the gap task (P = 0.04). Impaired saccade execution in reflexive tasks allowed discrimination between DLB versus Alzheimer's disease (sensitivity > or =60%, specificity > or =77%) and between PDD versus Parkinson's disease (sensitivity > or =60%, specificity > or =88%) when +/-1.5 standard deviations was used for group discrimination. We conclude that impairments in reflexive saccades may be helpful for differential diagnosis and are minimal when either cortical (Alzheimer's disease) or nigrostriatal neurodegeneration (Parkinson's disease) exists solely; however, they become prominent with combined cortical and subcortical neurodegeneration in PDD and DLB. The similarities in saccade performance in PDD and DLB underline the overlap between these conditions and underscore differences from Alzheimer's disease and Parkinson's disease.

Saccadic eye movement disturbances in whiplash patients with persistent complaints.

In order to analyse the possible basis of subjective complaints following whiplash injury, horizontal eye movements were examined in subjects with persistent complaints ('symptomatic group') and subjects who had completely recovered ('recovered group'). The results for the symptomatic and recovered groups were compared with those for age-matched, healthy volunteers (control group). A battery of different saccade paradigms was employed: two were reflexive saccade tasks including a gap and an overlap task, and two were intentional saccade tasks consisting of an antisaccade and a memory-guided saccade task. In addition, the symptomatic and recovered groups also underwent psychiatric evaluation in a structured clinical interview, and all groups were assessed for emotional functioning using the Beck Depression Inventory (BDI). The recovered group did not differ significantly from the control group in saccade performance and emotional functioning. The symptomatic group showed dissociation of their performances of reflexive and intentional saccade tasks: performance in reflexive saccade tasks was normal, but in intentional saccade tasks the symptomatic group showed significantly impaired inhibition of unwanted reflexive saccades, impaired saccade triggering (i.e. increased latency) and a higher percentage error in amplitude in memory-guided saccades. Based on clinical interviews, no signs of major depression or dysthymia were found in any of the groups. Compared with the other two groups, the symptomatic group had significantly higher overall BDI scores, but these resulted from BDI dimensions that were non-specific to depression, viz. 'physiological manifestations' (e.g. fatigue, sleep disturbance) or 'performance difficulty' (e.g. work inhibition). In summary, in the symptomatic group the pattern of eye movement disturbances together with normal performance in reflexive saccade tasks and impaired performance in the intentional saccade tasks, especially impaired inhibitory function, suggests dysfunction of prefrontal and frontal cortical structures.

Mass-movement and flood-induced deposits in Lake Ledro, southern Alps, Italy: implications for Holocene palaeohydrology and natural hazards

High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and riverbed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events) in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments have been finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events (SEs): light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography) of the organic matter present in soil, riverbed and lacustrine samples together with lake sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass-movements triggered by historical and pre-historical regional earthquakes dated to AD2005, AD1891, AD1045 and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11 495 cal. yr BP. Darkcoloured SEs develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and lignocellulosic debris) and are interpreted as resulting from intense hyperpycnal flood event. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 5mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting from the combination of heavy rainfall and snowmelt. The recurrence of flash flood events during the Holocene was, however, not high enough to affect pedogenesis processes and highlight several wet regional periods during the Holocene. The Holocene period is divided into four phases of environmental evolution. Over the first half of the Holocene, a progressive stabilization of the soils present through the catchment of Lake Ledro was associated with a progressive reforestation of the area and only interrupted during the wet 8.2 event when the soil destabilization was particularly important. Lower soil erosion was recorded during the mid-Holocene climatic optimum (8000-4200 cal. yr BP) and associated with higher algal production. Between 4200 and 3100 cal. yr BP, both wetter climate and human activities within the drainage basin drastically increased soil erosion rates. Finally, from 3100 cal. yr BP to the present-day, data suggest increasing and changing human land use.