Technological and mathematical advances have provided opportunities to investigate new approaches for the holistic quantification of complex biological systems. One objective of these approaches, including the multi-inverse deterministic approach proposed in this paper, is to deepen the understanding of biological systems through the structural development of a useful, best-fitted inverse mechanistic model. The objective of the present work was to evaluate the capacity of a deterministic approach, that is, the multi-inverse approach (MIA), to yield meaningful quantitative nutritional information. To this end, a case study addressing the effect of diet composition on sheep weight was performed using data from a previous experiment on saccharina (a sugarcane byproduct), and an inverse deterministic model (named Paracoa) was developed. The MIA successfully revealed an increase in the final weight of sheep with an increase in the percentage of corn in the diet. Although the soluble fraction also increased with increasing corn percentage, the effective nonsoluble degradation increased fourfold, indicating that the increased weight gain resulted from the nonsoluble substrate. A profile likelihood analysis showed that the potential best-fitted model had identifiable parameters, and that the parameter relationships were affected by the type of data, number of parameters and model structure. It is necessary to apply the MIA to larger and/or more complex datasets to obtain a clearer understanding of its potential.

The implantation and controlled release of growth factors can enhance the proliferation and differentiation of cells that promote new bone formation at defect sites. Therefore, chitosan polymer microspheres were prepared by the water-in-oil emulsion (W/O) method and solvent freeze-drying, using glutaraldehyde as an ionic crosslinker, along with the lyophilization of solvents, to microencapsulate growth factors, preventing denaturation. The microspheres were loaded with recombinant bone morphogenetic protein 2 (Rh-BMP-2). They were spherical in shape, with a rough surface ranging in particle size from 0.4 to 1.6 μm. The yield percentage with respect to the polymer was 70% and the BMP-2 load was regulated by the initial protein dose. BMP-2 release experiments were performed for 7 days in PBS solutions at pH 4 and 7.4. The results showed that the protein release rate was only 2% lower at pH 7.4. BMP-2/chitosan microspheres were compatible with the MG-63 cell line (ATCC®CRL-1427™Homo sapiens bone osteosarcoma) and could be considered drug delivery vehicles in bone tissue engineering applications.

The level of Kluane Lake, the largest lake in Yukon Territory, was lower than at present during most of the Holocene. The lake rose rapidly in the late seventeenth century to a level 12 m above present, drowning forest and stranding driftwood on a conspicuous high-stand beach, remnants of which are preserved at the south end of the lake. Kluane Lake fell back to near its present level by the end of the eighteenth century and has fluctuated within a range of about 3 m over the last 50 yr. The primary control on historic fluctuations in lake level is the discharge of Slims River, the largest source of water to the lake. We use tree ring and radiocarbon ages, stratigraphy and sub-bottom acoustic data to evaluate two explanations for the dramatic changes in the level of Kluane Lake. Our data support the hypothesis of Hugh Bostock, who suggested in 1969 that the maximum Little Ice Age advance of Kaskawulsh Glacier deposited large amounts of sediment in the Slims River valley and established the present course of Slims River into Kluane Lake. Bostock argued that these events caused the lake to rise and eventually overflow to the north. The overflowing waters incised the Duke River fan at the north end of Kluane Lake and lowered the lake to its present level. This study highlights the potentially dramatic impacts of climate change on regional hydrology during the Little Ice Age in glacierised mountains.

Considerable research has been conducted over the years to determine optimal rations for dairy cattle. Dean et al. extended earlier work through a comprehensive examination of milk production functions, isoquant shapes, and feed systems to maximize income over feed cost (IOFC) for a given point in time.

The Cortes geoduck (Panopea globosa) has been considered a Gulf of California (GC) endemic but anecdotal and unpublished evidence has suggested its presence in Bahía Magdalena (BM), on the Pacific coast of southern Baja California. Establishing the identity of geoduck clams and their distribution limits is not only of clear biological significance to understand their structural and functional variation, but is also of consequence for their conservation and management, given the multi-million dollar fishery they support in north-west Mexico. We analysed Panopea clams from Mexican populations, including BM, using an integrative approach including genetics, morphometrics, and an ecological niche model. Our genetic results (restriction fragment length polymorphisms of nuclear ribosomal DNA and mtDNA cytochrome c oxidase subunit I sequences) clearly identify BM geoducks as P. globosa, implying a significant geographical range expansion outside of the GC and refuting its status as endemic to the Gulf. On the other hand, clams from BM were phenotypically different (shell significantly higher) from other Mexican P. globosa and Panopea generosa specimens, which may account for the confusion in their morphological identification. The ecological niche model for P. globosa, integrating ecological and distributional data from the GC, revealed a very low probability (<10%) that this species could successfully occupy BM. Our results and those of others suggest that the Cortes geoduck population in BM may be adapted to specific environmental conditions differing from those experienced by conspecifics inside the Gulf and is likely isolated. This is highly relevant for the management plans of Mexican geoducks.

The objectives of this study were to assess the prevalence of fear of falling (FOF) among patients over age 60 with dizziness, falls, or syncope; and to analyze risk factors associated with FOF, including data from the tilt table test. This study included 200 older patients referred to a geriatric outpatient clinic specializing in dizziness, falls, and syncope. The primary outcome measure was the proportion of patients who experienced FOF (yes vs. no) and whether FOF restricted leaving home alone or performing activities of daily living. FOF occurred in 50 per cent of patients in this population. Among these, 44 per cent gave up going out alone and 10 per cent stopped doing basic activities of daily living. Beyond age 75, FOF was associated with recurrent dizziness, depression, and symptoms on standing, but not prior falls.

An experimental study of the mechanical properties of a Cu-Al-Be shape memory alloy is presented. The samples are tested in a cantilever arrangement. They consist of polycrystalline thin plates of shape memory material with a MS near 0 °C and a monocrystalline sample with MS near −90 °C. The measurements are made with strain gauges attached to the top side of the samples. In these conditions, strain Vs load curves are obtained. A polycrystalline sample is instrumented and tested and then it is cut into three samples for further testing. The results show a relationship between the transformation stress and the sample grain size which differs from the typical Hall-Petch relationship. The analysis of transformation plane stress diagrams shows the development of a stress component perpendicular to those induced by the applied load.

Logging history and population structure of the dry forest tree species Guaiacum coulteri are described for Oaxaca, Mexico. We propose that the species has been adversely affected by selective logging, with large individuals now being uncommon. We argue that the species is likely to have undergone similar changes elsewhere in its range and, following IUCN guidelines, propose that it is categorized as Endangered. Maintenance of G. coulteri as an understorey shrub may be possible given current land use practices in the area but recovery of populations of large individuals may be more difficult. Suggestions for future research are made.