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Designers faced with complex design problems use decomposition strategies to tackle manageable sub-problems. Recomposition strategies aims at synthesizing sub-solutions into a unique design proposal. Design theory describes the design process as a combination of decomposition and recomposition strategies. In this paper, we explore dynamic patterns of decomposition and recomposition strategies of design teams. Data were collected from 9 teams of professional engineers. Using protocol analysis, we examined the dominance of decomposition and recomposition strategies over time and the correlations between each strategy and design processes such as analysis, synthesis, evaluation. We expected decomposition strategies to peak early in the design process and decay overtime. Instead, teams maintain decomposition and recomposition strategies consistently during the design process. We observed fast iteration of both strategies over a one hour-long design session. The research presented provides an empirical foundation to model the behaviour of professional engineering teams, and first insights to refine theoretical understanding of the use decomposition and recomposition strategies in design practice.
Maternal mental health during pregnancy and postpartum predicts later emotional and behavioural problems in children. Even though most perinatal mental health problems begin before pregnancy, the consequences of preconception maternal mental health for children's early emotional development have not been prospectively studied.
We used data from two prospective Australian intergenerational cohorts, with 756 women assessed repeatedly for mental health problems before pregnancy between age 13 and 29 years, and during pregnancy and at 1 year postpartum for 1231 subsequent pregnancies. Offspring infant emotional reactivity, an early indicator of differential sensitivity denoting increased risk of emotional problems under adversity, was assessed at 1 year postpartum.
Thirty-seven percent of infants born to mothers with persistent preconception mental health problems were categorised as high in emotional reactivity, compared to 23% born to mothers without preconception history (adjusted OR 2.1, 95% CI 1.4–3.1). Ante- and postnatal maternal depressive symptoms were similarly associated with infant emotional reactivity, but these perinatal associations reduced somewhat after adjustment for prior exposure. Causal mediation analysis further showed that 88% of the preconception risk was a direct effect, not mediated by perinatal exposure.
Maternal preconception mental health problems predict infant emotional reactivity, independently of maternal perinatal mental health; while associations between perinatal depressive symptoms and infant reactivity are partially explained by prior exposure. Findings suggest that processes shaping early vulnerability for later mental disorders arise well before conception. There is an emerging case for expanding developmental theories and trialling preventive interventions in the years before pregnancy.
Parts I through III of this paper will examine several, increasingly comprehensive forms of aggregation, ranging from insurance reimbursement “lock-in” programs to PDMPs to completely unified electronic medical records (EMRs). Each part will advocate for the adoption of these aggregation systems and provide suggestions for effective implementation in the fight against opioid misuse. All PDMPs are not made equal, however, and Part II will, therefore, focus on several elements — mandating prescriber usage, streamlining the user interface, ensuring timely data uploads, creating a national data repository, mitigating privacy concerns, and training doctors on how to respond to perceived doctor-shopping — that can make these systems more effective. In each part, we will also discuss the privacy concerns of aggregating data, ranging from minimal to significant, and highlight the unique role of stigma in motivating these concerns. In Part IV, we will conclude by suggesting remedial steps to offset this loss of privacy and to combat the stigma around SUDs and mental health disorders in general.
We present the largest homogeneous survey of redshift > 4.4 damped Lyα systems (DLAs) using the spectra of 163 quasars that comprise the Giant Gemini GMOS (GGG) survey. With this survey we make the most precise high-redshift measurement of the cosmological mass density of neutral hydrogen, ΩHI. After correcting for systematic effects using a combination of mock and higher-resolution spectra, we find ΩHI= 0.98+0.20-0.18 × 10−3 at 〈z〉 = 4.9, assuming a 20% contribution from lower column density systems below the DLA threshold. By comparing to literature measurements at lower redshifts, we show that ΩHI can be described by the functional form ΩHI(z) ∝ (1 + z)0.4. This gradual decrease from z = 5 to 0 suggests that in the galaxies which dominate the cosmic star formation rate, Hi is a transitory gas phase fuelling star formation which must be continually replenished by more highly-ionized gas from the intergalactic medium, and from recycled galactic winds.
Nearly 258 million ha (28%) of the United States is publicly owned land that is managed by federal government agencies. For example, the US Department of Agriculture's Forest Service (USFS) manages over 77 million ha of national forests and grasslands for the benefit of the American public. Given its legal directive to manage multiple uses, it is not surprising that conflicts arise among stakeholders over how this land should be used (Lansky, 1992). The USFS has much discretion in how land is managed, yet must often balance conflicting values of public use and benefit (Nie, 2004). As national priorities, social preferences and public awareness of national forest goods, services and values have changed over time, USFS managers have faced increased pressure to balance consumptive uses with the need for environmental protection. Competing stakeholder demands coupled with increased environmental risks (wildfires, tree diseases and insect epidemics) have resulted in an escalating conservation conflict that is manifested in administrative appeals, lawsuits and a growing distrust of the agency.
Over time, the USFS has embraced new directions and management paradigms to reduce conflict. Some of these have been ecosystem management, adaptive management and now collaborative management (e.g. Holling, 1978; Maser, 1988; Franklin, 1992; Boyce and Haney, 1997; Wondolleck and Yaffee, 2000; Brown et al., 2004). These approaches reflect changing societal values, political pressures and new scientific information.
A persistent conflict has been the logging of trees in national forests and related impacts on forest ecosystems (Lansky, 1992). The USFS’ timber sale programme has supported jobs and community stability through economic development. Logging has also been a mechanism to reduce the risk of wildfire by reducing tree density (fuel for fires) and vertical stand diversity (‘ladder’ fuels; North et al., 2009). However, logging can also negatively affect forest integrity, watershed quality, wildlife, aesthetic and spiritual values of forests (Satterfield, 2002; North et al., 2009).
Efficient, reproducible, and precise methodologies for fabricating tissue engineering (TE) scaffolds using three-dimensional (3D) printing techniques are evaluated. Fusion deposition modeling, laser sintering, and photo printing each have limitations, including the materials that can be used with each printing system. However, new and promising resorbable materials are surfacing as alternatives to previously studied resorbable TE materials for 3D printing. One such resorbable polymer is poly(propylene fumarate) (PPF), which can be printed using photocross-linking 3D printing. The ability to print new materials opens up TE to a wide range of possibilities not previously available. The ability to control precise geometries, porosity, degradation, and functionalities present on 3D printable polymers such as PPF shows a new layer of complexity available for the design and fabrication of TE scaffolds.
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
Information about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
Infants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
Daily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
Most of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.
Porous, nanostructured silver samples were produced using a direct-write method where a nanoparticle aerosol consisting of particles with a mean size of approximately 5 nm were accelerated to speeds of approximately 1000 m/sec and impacted onto a translating substrate . The impacting particles have sufficient energy to stick to the substrate, allowing patterned thick films to be directly written from the aerosol without a mask. Unlike other low temperature processing routes for achieving patterned films, no organics are added that can interfere with postdeposition processing. Typical films are 5- 100 μm thick, up to several centimeters long, and have an as-deposited relative densities as high as 70% of bulk Ag. Compression tests were carried out in steps at room temperature and at 150°C under constant displacement rates. Local strain and densification were measured by optical profilometry between each compression step. The results can be used as a starting point to better understand the mechanisms that govern plasticity, creep, and sintering in nanostructured, porous silver at low processing temperatures.
Understanding the timing of mountain glacier and paleolake expansion and retraction in the Great Basin region of the western United States has important implications for regional-scale climate change during the last Pleistocene glaciation. The relative timing of mountain glacier maxima and the well-studied Lake Bonneville highstand has been unclear, however, owing to poor chronological limits on glacial deposits. Here, this problem is addressed by applying terrestrial cosmogenic 10Be exposure dating to a classic set of terminal moraines in Little Cottonwood and American Fork Canyons in the western Wasatch Mountains. The exposure ages indicate that the main phase of deglaciation began at 15.7 ± 1.3 ka in both canyons. This update to the glacial chronology of the western Wasatch Mountains can be reconciled with previous stratigraphic observations of glacial and paleolake deposits in this area, and indicates that the start of deglaciation occurred during or at the end of the Lake Bonneville hydrologic maximum. The glacial chronology reported here is consistent with the growing body of data suggesting that mountain glaciers in the western U.S. began retreating as many as 4 ka after the start of northern hemisphere deglaciation (at ca. 19 ka).
Although highly magnetostrictive thin films of Terfenol-D have been produced by a variety of methods, high-quality thick films have proved to be far more challenging to produce. To date, thick film processes have resulted in nanoparticulate films that contain significant porosity that reduces stiffness and results in oxidation and poor magnetostrictive performance. With the goal of understanding microstructural and compositional factors that affect performance, nanoparticulate Terfenol-D thick films were produced by laser ablation of microparticle aerosols combined with supersonic impaction. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, x-ray photon spectroscopy, and magnetic measurements were performed on nanoparticles and on films as-deposited and after annealing in vacuum or in a reducing atmosphere. These measurements show that segregation occurs during oxidation of the films, prior to annealing, and results in films with poor magnetostriction. The segregation persists during annealing with no visible changes to the morphology or density of the nanoparticulate films exposed to temperatures as high as 800 °C. These results suggest that oxidation and segregation must be avoided to produce highly magnetostrictive thick films.