1,433 research outputs found
Defining Feedback: Understanding Students’ Perceptions of Feedback in the Introductory Communication Course
Feedback is an essential part of the teaching/learning processes. This statement is especially true in the introductory communication course where students receive feedback throughout the presentational speaking process. This paper explores how students define useful feedback based on 1,600 qualitative questionnaires that asked students about their perceptions of feedback. A thematic analysis of a randomly selected subset of 163 responses uncovered two themes: (1) feedback content characteristics (e.g., specific, constructive, praiseworthy, and purposive) and (2) process of instructor-provided feedback (e.g., iterative, timely). Based on these findings, a set of best practices for providing feedback is offered as a means to improve teaching/learning in the introductory communication course
A superoxide dismutase biosensor for measuring the antioxidant capacity of blueberry based integrators
The antioxidant capacity of capsules containing blueberry based products which are included among the group of integrators owing to their antioxidant capacity and produced by various films was investigated. The results of the investigation are compared to rank these products in order to their antioxidant capacity. In order to measure antioxidant capacity, our laboratory has recently developed a special electrochemical method based on a superoxide dismutase (SOD) biosensor to determine the superoxide radical. The results obtained by applying the SOD biosensor method to various blueberry based integrators were compared with the results obtained with the spectrophotometric (FRAP) method based on N,N-dimethyl-p-phenylendiamine (DMPD-FeCl3) and with those obtained also using the ORAC fluorimetric (TRAP) method. One of the more interesting aspect of the article is the good agreement it evidences of the results of the three methods for measuring antioxidant capacity. The three methods differ among themselves: an Electron Transfer (ET) method, a Hydrogen Atom Trasnfer Metod (HAT) and an electrochemical based biosensor method of the Morning Superoxide Radical (MSR) type. It is also shown how the antioxidant capacity of the fresh vegetable is in any case always greater then of any food supplement obtained from the same type of vegetable
Integrated geophysical and geological investigations applied to sedimentary rock mass characterization
The Salento Peninsula (south-eastern Italy) is characterized by sedimentary rocks. The carbonatic nature of the
rocks means they are affected by karst phenomena, forming such features as sinkholes, collapsed dolines and caverns,
as a result of chemical leaching of carbonates by percolating water. The instability of these phenomena often
produces land subsidence problems. The importance of these events is increasing due to growing urbanization, numerous
quarries affecting both the subsoil and the surface, and an important coastline characterized by cliffs. This
paper focuses on geological and geophysical methods for the characterization of soft sedimentary rock, and presents
the results of a study carried out in an urban area of Salento. Taking the Q system derived by Barton (2002) as
the starting point for the rock mass classification, a new approach and a modification of the Barton method are proposed.
The new equation proposed for the classification of sedimentary rock mass (Qsrm) takes account of the permeability
of the rock masses, the geometry of the exposed rock face and their types (for example, quarry face,
coastal cliff or cavity), the nature of the lithotypes that constitute the exposed sequence, and their structure and texture.
This study revises the correlation between Vp and Q derived by Barton (2002), deriving a new empirical equation
correlating P-wave velocities and Qsrm values in soft sedimentary rock. We also present a case history in which
stratigraphical surveys, Electrical Resistivity Tomography (ERT), and seismic surveys were applied to in situ investigations
of subsidence phenomena in an urban area to estimate rock mass quality. Our work shows that in the
analysis of ground safety it is important to establish the rock mass quality of the subsurface structures; geophysical
exploration can thus play a key role in the assessment of subsidence risk
Crystal structure and phonon softening in Ca3Ir4Sn13
We investigated the crystal structure and lattice excitations of the ternary
intermetallic stannide Ca3Ir4Sn13 using neutron and x-ray scattering
techniques. For T > T* ~ 38 K the x-ray diffraction data can be satisfactorily
refined using the space group Pm-3n. Below T* the crystal structure is
modulated with a propagation vector of q = (1/2, 1/2, 0). This may arise from a
merohedral twinning in which three tetragonal domains overlap to mimic a higher
symmetry, or from a doubling of the cubic unit cell. Neutron diffraction and
neutron spectroscopy results show that the structural transition at T* is of a
second-order, and that it is well described by mean-field theory. Inelastic
neutron scattering data point towards a displacive structural transition at T*
arising from the softening of a low-energy phonon mode with an energy gap of
Delta(120 K) = 1.05 meV. Using density functional theory the soft phonon mode
is identified as a 'breathing' mode of the Sn12 icosahedra and is consistent
with the thermal ellipsoids of the Sn2 atoms found by single crystal
diffraction data
Relation of Abdominal Fat Depots to Systemic Markers of Inflammation in Type 2 Diabetes
OBJECTIVE: Both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) have been linked to systemic inflammation in nondiabetic cohorts. We examined the relationships between VAT and SAT and systemic inflammatory markers in a large well-characterized cohort of subjects with type 2 diabetes. RESEARCH DESIGN AND METHODS: Three hundred eighty-two subjects with type 2 diabetes in the CHICAGO (Carotid Intima-Media Thickness in Atherosclerosis Using Pioglitazone) study cohort underwent abdominal computed tomography to determine SAT and VAT distribution. Fasting blood was obtained for measurement of inflammatory markers. The relationships between inflammatory markers and BMI, SAT, and VAT were examined using regression models adjusted for age, sex, diabetes treatment, duration of diabetes, smoking, statin use, and A1C. RESULTS: VAT was positively related to CRP, monocyte chemoattractant protein (MCP), intracellular adhesion molecule (ICAM)-1, and plasminogen activator inhibitor type 1 (PAI-1) antigen before adjustment for BMI. After adjustment for BMI, the relationship to CRP was lost but positive associations with MCP (P < 0.01), PAI-1 (P < 0.0001), ICAM-1 (P < 0.01), and vascular cell adhesion molecule (P = 0.01) were evident. BMI was positively related to CRP (P < 0.0001) and IL-6 (P < 0.01) even after adjustment for VAT and SAT. SAT was not related to any inflammatory marker after adjustment for BMI. CONCLUSIONS: In this large group of subjects with type 2 diabetes, BMI was most strongly associated with CRP and IL-6 levels. SAT was not associated with markers of systemic inflammation. The size of the VAT depot provided information additional to that provided by BMI regarding inflammatory markers that are strongly related to vascular wall remodeling and coagulation. Our findings suggest that adipose tissue distribution remains an important determinant of systemic inflammation in type 2 diabetes.National Institutes of Health (DK-71711); University of Illinois at Chicag
Oxidative Stress Regulates Adipocyte Apolipoprotein E and Suppresses Its Expression in Obesity
OBJECTIVE—Endogenous expression of apolipoprotein E (apoE) has a significant impact on adipocyte lipid metabolism and is markedly suppressed in obesity. Adipose tissue oxidant stress is emerging as an important mediator of adipocyte dysfunction. These studies were undertaken to evaluate the role of oxidant stress for regulation of adipocyte apoE
Hypertriglyceridemic Waist Phenotype Predicts Increased Visceral Fat in Subjects With Type 2 Diabetes
OBJECTIVE: Greater accumulation of visceral fat is strongly linked to risk of cardiovascular disease. However, elevated waist circumference by itself does not always identify individuals with increased visceral fat. RESEARCH DESIGN AND METHODS: We examined 375 subjects with type 2 diabetes from the CHICAGO cohort for presence of hypertriglyceridemic waist phenotype (waist circumference >90 cm in men or >85 cm in women, in conjunction with a plasma triglyceride concentration of ≥177 mg/dl) to determine its usefulness for identifying subjects with increased amounts of visceral fat. We divided subjects into three groups: group 1 (low waist circumference and low triglycerides; waist circumference ≤90 cm in men or ≤85 cm in women and triglyceride <177 mg/dl, n = 18), group 2 (high waist circumference and low triglycerides; waist circumference >90 cm in men or >85 cm in women and triglycerides <177 mg/dl, n = 230), and group 3 (high waist circumference and high triglycerides; waist circumference >90 cm in men or >85 cm in women and triglycerides ≥177 mg/dl, n = 127). RESULTS: Subjects in group 3 had significantly higher visceral fat (P < 0.0001), A1C (P < 0.01), and coronary artery calcium (P < 0.05) compared with group 2, despite similar age, BMI, and waist circumference. The relationship of the phenotype to atherosclerosis, however, was attenuated by adjustment for HDL cholesterol, triglyceride-rich lipoprotein cholesterol, apolipoprotein B, or LDL particle number. CONCLUSIONS: The presence of hypertriglyceridemic waist phenotype in subjects with type 2 diabetes identifies a subset with greater degree of visceral adiposity. This subset also has greater degree of subclinical atherosclerosis that may be related to the proatherogenic lipoprotein changes.Takeda Global Research and Development; National Institutes of Health (DK 71711); University of Illinois at Chicag
- …