OBJECTIVE To assess the effect of a specialist telemedicine intervention for improving diabetes care using the chronic care model (CCM). PARTICIPANTS AND METHODS As part of the CCM, 97 primary care ...physicians at 6 primary care practices in Rochester, MN, referred 639 patients to an on-site diabetes educator between July 1, 2001, and December 31, 2003. On first referral, physicians were centrally randomized to receive a telemedicine intervention (specialty advice and evidence-based messages regarding medication management for cardiovascular risk) or no intervention, keeping outcome assessors and data analysts blinded to group assignment. After each subsequent clinical encounter, endocrinologists reviewed an abstract from the patient's electronic medical record and provided management recommendations and supporting evidence to intervention physicians via e-mail. Control physicians received e-mail with periodic generic information about cardiovascular risk reduction in diabetes. Outcome measures included diabetes care processes (diabetes test completion), outcomes (metabolic and cardiovascular risk factors, estimated coronary artery disease risk), and patient costs (payer perspective). RESULTS During the intervention, 951 (70%) of the 1361 endocrinology reviews detected performance gaps and resulted in a message; primary care physicians reported using 49% of messages in patient care. With a mean of 21 months' follow-up, the intervention, compared with control, did not significantly enhance metabolic outcomes or reduce estimated risk of coronary artery disease (adjusted mean difference, -1%; 95% confidence interval, -19% to 17%). The intervention group incurred lower costs ( P =.02) but not in diabetes-related costs. CONCLUSION Specialty telemedicine did not significantly enhance the value of CCM in primary care. Trial Registration: clinicaltrials.gov identifier: NCT00421850
Doped antiferromagnets host a vast array of physical properties and learning how to control them is one of the biggest challenges of condensed matter physics. La 1.67 Sr 0.33 NiO 4 (LSNO) is a ...classic example of such a material. At low temperatures holes introduced via substitution of La by Sr segregate into lines to form boundaries between magnetically ordered domains in the form of stripes. The stripes become dynamic at high temperatures, but LSNO remains insulating presumably because an interplay between magnetic correlations and electron–phonon coupling localizes charge carriers. Magnetic degrees of freedom have been extensively investigated in this system, but phonons are almost completely unexplored. We searched for electron–phonon anomalies in LSNO by inelastic neutron scattering. Giant renormalization of plane Ni–O bond-stretching modes that modulate the volume around Ni appears on entering the dynamic charge stripe phase. Other phonons are a lot less sensitive to stripe melting. Dramatic overdamping of the breathing modes indicates that dynamic stripe phase may host small polarons. We argue that this feature sets electron–phonon coupling in nickelates apart from that in cuprates where breathing phonons are not overdamped and point out remarkable similarities with the colossal magnetoresistance manganites.
The A-site spinel material CoAl2O4 is a physical realization of the frustrated diamond-lattice antiferromagnet, a model in which unique incommensurate or “spin-spiral-liquid” ground states are ...predicted. Our previous single-crystal neutron scattering study instead classified it as a “kinetically inhibited” antiferromagnet, where the long-ranged correlations of a collinear Néel ground state are blocked by the freezing of domain-wall motion below a first-order phase transition at T*=6.5 K. This paper provides new data sets from a number of experiments, which support and expand this work in several important ways. We show that the phenomenology leading to the kinetically inhibited order is unaffected by sample measured and instrument resolution, while new low-temperature measurements reveal spin correlations are unchanging between T=2 K and 250 mK, consistent with a frozen state. Polarized diffuse neutron measurements show several interesting magnetic features, which can be entirely explained by the existence of short-ranged Néel order. Finally, and crucially, this paper presents some neutron scattering studies of single crystalline MnAl2O4, which acts as an unfrustrated analog to CoAl2O4 and shows all the hallmarks of a classical antiferromagnet with a continuous phase transition to Néel order at TN=39 K. Direct comparison between the two compounds indicates that CoAl2O4 is unique, not in the nature of high-temperature diffuse correlations, but rather in the nature of the frozen state below T*. The higher level of cation inversion in the MnAl2O4 sample indicates that this behavior is primarily an effect of greater next-nearest-neighbor exchange.
Decades of research have produced substantial data on elk (Cervus elaphus) diets in winter, when foraging conditions are most likely to affect population dynamics. Using data from 72 studies ...conducted in western North America between 1938 and 2002, we collated data on elk diets and environmental variables. We used these data to quantify diet selection by elk and to test whether variation in elk diets is associated with habitat type, winter severity, period of winter, human hunting, and study method. Graminoids (grasses and grass-like plants such as sedges) dominated elk diets and consistently occurred at a higher proportion in the diet than in elk foraging habitats, indicating preference. Forbs commonly made up ≤5% of the diet, with no evidence for preference; we conclude that forb use is largely incidental to grazing for graminoids. Browse was consumed in proportion to its availability, implying that the amount of browse in the diet was primarily determined by habitat use rather than selection. Comparing the diets of elk and sympatric ruminants, elk consistently selected graminoids more strongly than sympatric ruminants with the exception of bison (Bison bison), suggesting that elk are not environmentally forced to adopt the graminoid-biased diet that they normally select. The proportion of open meadows and grasslands on winter ranges was strongly and positively associated with graminoid consumption by elk. The proportion of graminoids in the diet was significantly lower in elk experiencing severe winter conditions or predation risk from human hunting. The period of winter (early, middle, and late) had only small effects on elk diets, as did the method by which the diet was determined. Overall, variation in elk diets is well-explained by a consistent tendency to select graminoids if available, modified by winter habitat type, predation risk, and winter severity, which can constrain habitat selection and access to grazing opportunities. To fully understand variation in foraging behavior, biologists should recognize these broad patterns when interpreting resource selection data. Managers should recognize that inconspicuous behavioral responses to environmental stimuli can alter the diet in ways that probably carry nutritional consequences.
The specific heat of Ce3Co4Sn13 exhibits a crossover from heavy Fermion behavior with antiferromagnetic correlations at low field to single impurity Kondo behavior above 2T. We have performed neutron ...diffraction measurements in magnetic fields up to 6T on single crystal samples. The (001) position shows a dramatic increase in intensity in field which appears to arise from static polarization of the 4f level and which at 0.14K also exhibits an anomaly near 2T reflecting the crossover to single impurity behavior.
Genes transformed into plants are usually inherited in a regular Mendelian manner. There are, however, transformants in which the selectable trait fails to segregate as expected. Genetic analysis of ...the kanamycin-resistance (KanR) trait in >900 independent transformants of Arabidopsis revealed that 9% produced progeny families with an enormous deficiency of KanR individuals. Self-pollination of individual KanR plants from these families revealed lines that continued to segregate for a deficiency of KanR seedlings. In subsequent generations, the segregation ratio in these families stabilized at approximately 1 KanR:3 KanS. Molecular analyses showed that the deficiency of KanR individuals reflected the complete absence of the introduced DNA. Reciprocal backcrosses to untransformed plants showed unequal transmission of the KanR trait through the gametes in these exceptional lines. In five cases, this was primarily a failure of transmission through the microgametophyte (pollen) and in the other two cases, primarily a failure of transmission through the megagametophyte (embryo sac or egg). The number of seeds per silique was reduced by 50% in the latter two lines. We conclude that our exceptional transformants contain T-DNA insertions that delete or disrupt genes essential for gametophytic growth and development.
Inelastic neutron scattering measurements have been performed to investigate the spin waves of the quasi-one-dimensional antiferromagnetic ladder compound BaFe2S3, where a superconducting transition ...was observed under pressure H. Takahashi et al., Nat. Mater. 14, 1008 (2015); T. Yamauchi et al., Phys. Rev. Lett. 115, 246402 (2015). By fitting the spherically averaged experimental data collected on a powder sample to a Heisenberg Hamiltonian, we find that the one-dimensional antiferromagnetic ladder exhibits a strong nearest-neighbor ferromagnetic exchange interaction (SJR=−71±4 meV) along the rung direction, an antiferromagnetic SJL=49±3 meV along the leg direction, and a ferromagnetic SJ2=−15±2 meV along the diagonal direction. Our data demonstrate that the antiferromagnetic spin excitations are a common characteristic for the iron-based superconductors, while specific relative values for the exchange interactions do not appear to be unique for the parent states of the superconducting materials.
Low temperature behavior of the heavy fermion Ce3Co4Sn13 CHRISTIANSON, A. D; GARDNER, J. S; KANG, H. J ...
Journal of magnetism and magnetic materials,
03/2007, Letnik:
310, Številka:
2
Conference Proceeding, Journal Article
Recenzirano
The compound Ce3Co4Sn13 is an extremely heavy cubic heavy fermion system with a low temperature electronic specific heat of order . If the compound is nonmagnetic, it would be one of the heaviest ...nonmagnetic Ce-based heavy fermions reported to date and therefore would be expected to lie extremely close to a quantum critical point. However, a broad peak of unknown origin is observed at 0.8K in the specific heat and magnetic susceptibility, suggesting the possibility of antiferromagnetic order. We present neutron diffraction data from polycrystalline samples which do not show any sign of magnetic scattering below 0.8K. In addition, we present inelastic neutron scattering data from a single crystal sample which is consistent with the 1.2K energy scale for Kondo spin fluctuations determined from specific heat measurements.
Structural properties of LaCu6−xAgx have been investigated using neutron and x-ray diffraction, and resonant ultrasound spectroscopy (RUS) measurements. Diffraction measurements indicate a continuous ...structural transition from orthorhombic (Pnma) to monoclinic (P21/c) structure. RUS measurements show softening of natural frequencies at the structural transition, consistent with the elastic nature of the structural ground state. The structural transition temperatures in LaCu6−xAgx decrease with Ag composition until the monoclinic phase is completely suppressed at xc=0.225. All of the evidence is consistent with the presence of an elastic quantum critical point in LaCu6−xAgx.
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