Genetic Map of Bacteriophage [var phi]X174

Bacteriophage [var phi]X174 temperature-sensitive and nonsense mutations in eight cistrons were mapped by using two-, three-, and four-factor genetic crosses. The genetic map is circular with a total length of 24 × 10−4wt recombinants per progeny phage. The cistron order is D-E-F-G-H-A-B-C. High negative interference is seen, consistent with a small closed circular deoxyribonucleic acid molecule as a genome

Observations on the Overwintering Potential of the Striped Cucumber Beetle (Coleoptera: Chrysomelidae) in Southern Minnesota

The striped cucumber beetle, Acalymma vittatum (Fabricius) (Coleoptera: Chrysomelidae), is an important pest of cucurbit crops. However, the overwinter- ing capacity of this pest in temperate regions is poorly understood. In this study, the in-field survival of A. vittatum was examined during three consecutive winters. In addition, the supercooling points of A. vittatum were determined as an index of cold hardiness for adults. During each winter, the survival of adults decreased significantly through time, with no individuals surviving until spring. By comparing the supercooling points and in-field survival of adults to soil temperatures, it appears that winter temperatures in Minnesota are cold enough to induce freezing of the beetles. Moreover, a considerable amount of mortality occurred before minimum monthly soil temperatures dropped below the supercooling point of overwintering individuals, suggesting the occurrence of prefreeze mortality. An improved understanding of the response of A. vittatum to winter temperatures in temperate regions may aid in early season management of this pest

Dwelling Quietly in the Rich Club: Brain Network Determinants of Slow Cortical Fluctuations

For more than a century, cerebral cartography has been driven by investigations of structural and morphological properties of the brain across spatial scales and the temporal/functional phenomena that emerge from these underlying features. The next era of brain mapping will be driven by studies that consider both of these components of brain organization simultaneously -- elucidating their interactions and dependencies. Using this guiding principle, we explored the origin of slowly fluctuating patterns of synchronization within the topological core of brain regions known as the rich club, implicated in the regulation of mood and introspection. We find that a constellation of densely interconnected regions that constitute the rich club (including the anterior insula, amygdala, and precuneus) play a central role in promoting a stable, dynamical core of spontaneous activity in the primate cortex. The slow time scales are well matched to the regulation of internal visceral states, corresponding to the somatic correlates of mood and anxiety. In contrast, the topology of the surrounding "feeder" cortical regions show unstable, rapidly fluctuating dynamics likely crucial for fast perceptual processes. We discuss these findings in relation to psychiatric disorders and the future of connectomics.Comment: 35 pages, 6 figure

Tuning the Kondo effect with a mechanically controllable break junction

We study electron transport through C60 molecules in the Kondo regime using a mechanically controllable break junction. By varying the electrode spacing, we are able to change both the width and height of the Kondo resonance, indicating modification of the Kondo temperature and the relative strength of coupling to the two electrodes. The linear conductance as a function of T/T_K agrees with the scaling function expected for the spin-1/2 Kondo problem. We are also able to tune finite-bias Kondo features which appear at the energy of the first C60 intracage vibrational mode.Comment: 4 pages with 4 figure

Musculoskeletal education: a curriculum evaluation at one university

<p>Abstract</p> <p>Background</p> <p>The increasing burden of illness related to musculoskeletal diseases makes it essential that attention be paid to musculoskeletal education in medical schools. This case study examines the undergraduate musculoskeletal curriculum at one medical school.</p> <p>Methods</p> <p>A case study research methodology used quantitative and qualitative approaches to systematically examine the undergraduate musculoskeletal course at the University of Calgary (Alberta, Canada) Faculty of Medicine. The aim of the study was to understand the strengths and weaknesses of the curriculum guided by four questions: (1) Was the course structured according to standard principles for curriculum design as described in the Kern framework? (2) How did students and faculty perceive the course? (3) Was the assessment of the students valid and reliable? (4) Were the course evaluations completed by student and faculty valid and reliable?</p> <p><b>Results</b></p> <p>The analysis showed that the structure of the musculoskeletal course mapped to many components of Kern's framework in course design. The course had a high level of commitment by teachers, included a valid and reliable final examination, and valid evaluation questionnaires that provided relevant information to assess curriculum function. The curricular review identified several weaknesses in the course: the apparent absence of a formalized needs assessment, course objectives that were not specific or measurable, poor development of clinical presentations, small group sessions that exceeded normal 'small group' sizes, and poor alignment between the course objectives, examination blueprint and the examination. Both students and faculty members perceived the same strengths and weaknesses in the curriculum. Course evaluation data provided information that was consistent with the findings from the interviews with the key stakeholders.</p> <p>Conclusions</p> <p>The case study approach using the Kern framework and selected questions provided a robust way to assess a curriculum, identify its strengths and weaknesses and guide improvements.</p

Observations on the Overwintering Potential of the Striped Cucumber Beetle (Coleoptera: Chrysomelidae) in Southern Minnesota

The striped cucumber beetle, Acalymma vittatum (Fabricius) (Coleoptera: Chrysomelidae), is an important pest of cucurbit crops. However, the overwinter- ing capacity of this pest in temperate regions is poorly understood. In this study, the in-field survival of A. vittatum was examined during three consecutive winters. In addition, the supercooling points of A. vittatum were determined as an index of cold hardiness for adults. During each winter, the survival of adults decreased significantly through time, with no individuals surviving until spring. By comparing the supercooling points and in-field survival of adults to soil temperatures, it appears that winter temperatures in Minnesota are cold enough to induce freezing of the beetles. Moreover, a considerable amount of mortality occurred before minimum monthly soil temperatures dropped below the supercooling point of overwintering individuals, suggesting the occurrence of prefreeze mortality. An improved understanding of the response of A. vittatum to winter temperatures in temperate regions may aid in early season management of this pest

Knee Loading Due to Varus and External Rotation in Gait Supports Medial Compartment Wear in Total Knee Arthroplasty

Malalignment of the lower extremity may be a cause for gonarthrosis and failure of total knee prosthetic components. Neutral lower limb alignment is considered straight alignment of the axes formed from the center of the femoral head to the center of the knee and from the center of the knee to the center of the ankle joint (the mechanical axes of the thigh and shank). Malalignment of the mechanical axis (measured by δv, the angle between the femoral and the tibial mechanical axes) occurs when varus moves the line of action farther medially from the knee joint center. Malalignment due to varus results in increases in medial compartment loading and has been attributed to medial compartment articular cartilage degeneration. External rotation of the hip and knee compared to the direction of gait is another form of malalignment. In external rotation, the knee displaces from the midline at stance phase. Knee loading and the consequences of external rotation on cartilage degeneration are not well understood. The purpose of our study was to develop a mathematical model that would calculate forces and moments in knees for gait and study how they vary with varus and external rotation malalignment. An additional objective was to develop a finite element model of total knee replacement to study stress patterns on the polyethylene insert during malaligned gait. We hypothesized that medial compartment loads would be increased by both varus and external rotation alignment of the knee compared to the direction of gait. We also hypothesize that stress patterns on total knee replacement (TKR) inserts under conditions related to malaligned gait will correlate with wear patterns observed in retrieval studies. It was found that for varus and external rotation, there is a shift towards adduction moment, which resulted in an increase in medial compartment loads, supporting our hypothesis. It was also found that the malalignment in gait results in alterations in tibial tray load magnitudes and load distribution that support elevated wear in the medial compartment as observed clinically

Assortative human pair-bonding for partner ancestry and allelic variation of the dopamine receptor D4 (DRD4) gene

The 7R allele of the dopamine receptor D4 gene has been associated with attention-deficit hyperactivity disorder and risk taking. On the cross-population scale, 7R allele frequencies have been shown to be higher in populations with more of a history of long-term migrations. It has also been shown that the 7R allele is associated with individuals having multiple-ancestries. Here we conduct a replication of this latter finding with two independent samples. Measures of subjects&#x2019; ancestry are used to examine past reproductive bonds. The individuals&#x2019; history of inter-racial/ancestral dating and their feelings about this are also assessed. Tentative support for an association between multiple ancestries and the 7R allele were found. These results are dependent upon the method of questioning subjects about their ancestries. Inter-racial dating and feelings about inter-racial pairing were not related to the presence of the 7R allele. This might be accounted for by secular trends that might have substantively altered the decision-making process employed when considering relationships with individuals from different groups. This study provides continued support for the 7R allele playing a role in migration and/or mate choice patterns. However, replications and extensions of this study are needed and must carefully consider how ancestry/race is assessed