Vitamin A and ascorbic acid nutriture and snacking patterns of female adolescents

A cross-sectional nutritional survey of 198 adolescent females in Guilford County, North Carolina, was conducted to assess vitamin A and ascorbic acid nutritional status and to investigate and describe snacking patterns. Subjects included black and white girls, ages 12, 14, and 16 years. Data collected included measurement of serum levels of vitamin A and beta-carotene, dietary analysis of meals and snacks from 24-hour food recalls, investigation of snacking patterns from a dietary history interview, and frequency intakes and preferences for 56 food items high in vitamin A and ascorbic acid. Mean dietary intakes for vitamin A (5995 IU) and ascorbic acid (155 mg) exceeded the RDA, but ascorbic acid intake was marginal for 21 percent of the subjects and vitamin A intake was marginal for 12 percent. Twelve-year-old girls had better nutritional status for vitamin A than did older girls. White girls consumed more ascorbic acid than did blacks. Vitamin supplements contributed significantly to nutrient intake

3D Analysis of chromosome architecture: advantages and limitations with SEM

Three-dimensional mitotic plant chromosome architecture can be investigated with the highest resolution with scanning electron microscopy compared to other microscopic techniques at present. Specific chromatin staining techniques making use of simultaneous detection of back-scattered electrons and secondary electrons have provided conclusive information on the distribution of DNA and protein in barley chromosomes through mitosis. Applied to investigate the structural effects of different preparative procedures, these techniques were the groundwork for the ``dynamic matrix model{''} for chromosome condensation, which postulates an energy-dependent process of looping and bunching of chromatin coupled with attachment to a dynamic matrix of associated protein fibers. Data from SEM analysis shows basic higher order chromatin structures: chromomeres and matrix fibers. Visualization of nanogold-labeled phosphorylated histone H3 (ser10) with high resolution on chromomeres shows that functional modifications of chromatin can be located on structural elements in a 3D context. Copyright (C) 2005 S. Karger AG, Basel

An explanatory mixed-methods study of instructional coaching practices and their relationship to student achievement

The purposes of this study were to examine the nature of high school instructional coaching implementation, explore a possible relationship between instructional coaching and student achievement, and identify aspects of a successful instructional coaching program. This study was unique because of the exploration of instructional coaching practices in relation to student achievement. Qualitative research on coaching best practices and even instructional improvement are available, but few studies have delved into the primary goal of high school instructional coaching: improving student learning and achievement. This study used a mixed-methods design. The sampling frame was the 115 North Carolina public school districts. Of these 115 school districts, 39 employed high school instructional coaches at some point between 2005 and 2010. Data for the study included survey results from the 115 NC school districts, NC School Report Card Data, and interviews with the high school instructional coach and curriculum director for the selected district. Implementation of high school instructional coaching varied across the state. Employment status included full-time instructional coaches, part-time administrators, part-time teachers, and part-time employment only. Coaches differed in their work with specific content areas and in the school and district level initiatives they supported. Coaches differed in the professional development they were provided and in the number of times they were expected to meet with principals in the high schools they served. Some of the coaches worked at one high school, while others were supporting as many as eight high schools in their district. The activities coaches directed differed markedly as well, but most coaches were expected to support teachers in lesson planning and delivery. No relationship was found between student achievement and the number of schools a coach served, coaches‘ support of Professional Learning Communities, coach professional development, relationship confidentiality, or typical coaching activities. However, the frequency of principal and coach meetings was related to student achievement. The district demonstrating the most significant growth in student achievement noted almost daily interaction between the coach and principal. This particular coach both performed traditional instructional coaching duties and taught students a minimum of 40 minutes every day. Districts are encouraged to pursue some of the nontraditional coaching activities the interviewed coach noted, particularly her continued work with students as a tutor and classroom teacher. In addition, policy makers may want to consider priority hiring of coaches who have had successful teaching experiences at the school in which they will coach. Further research should be conducted in the state to determine if a relationship exists between instructional coaching in grades K-8 and student achievement. In addition, qualitative research on specific coaching practices should be conducted comparing the high school coaching districts demonstrating growth over time in student achievement and those who saw no gains

Cytogenetic characterization of two species of Frieseomelitta Ihering, 1912 (Hymenoptera, Apidae, Meliponini)

The cytogenetic analysis of Frieseomelitta dispar and F. francoi revealed the chromosome numbers 2n = 30 and n = 15 and a karyotypic formula 2K = 4M+2Mt+4A+20AM. The number of chromosomes observed was consistent with those reported for other Frieseomelitta species. The occurrence of the Mt chromosome and other features of the karyotype formulae suggest a close relationship between F. dispar, F. francoi and F. varia. Nevertheless, it was possible to differentiate the karyotypes of the species by DAPI/CMA3 staining, which revealed GC-rich regions on two chromosome pairs of F. dispar: one acrocentric and one pseudoacrocentric. In F. francoi, the same kinds of regions were observed on a pair of metacentrics and on a pair of acrocentrics. Our analysis also confirmed the chromosome number conservation in Frieseomelitta and suggests that infrequent pericentric inversion could constitute a synapomorphy for the group including F. dispar, F. francoi, and F. varia

A stitch in time: Efficient computation of genomic DNA melting bubbles

Background: It is of biological interest to make genome-wide predictions of the locations of DNA melting bubbles using statistical mechanics models. Computationally, this poses the challenge that a generic search through all combinations of bubble starts and ends is quadratic. Results: An efficient algorithm is described, which shows that the time complexity of the task is O(NlogN) rather than quadratic. The algorithm exploits that bubble lengths may be limited, but without a prior assumption of a maximal bubble length. No approximations, such as windowing, have been introduced to reduce the time complexity. More than just finding the bubbles, the algorithm produces a stitch profile, which is a probabilistic graphical model of bubbles and helical regions. The algorithm applies a probability peak finding method based on a hierarchical analysis of the energy barriers in the Poland-Scheraga model. Conclusions: Exact and fast computation of genomic stitch profiles is thus feasible. Sequences of several megabases have been computed, only limited by computer memory. Possible applications are the genome-wide comparisons of bubbles with promotors, TSS, viral integration sites, and other melting-related regions.Comment: 16 pages, 10 figure

Autobiographical memory and hierarchical search strategies in depressed and non-depressed participants

Background: There is a growing body of literature showing individuals with depression and other trauma-related disorders (e.g., posttraumatic stress disorder) recall more overgeneral and less specific autobiographical memories compared to normal participants. Although the mechanisms underlying overgeneral memory are quite clear, the search strategy operated within the autobiographical knowledge base, at time of recollection, requires further exploration. The current study aimed to examine the hierarchical search sequence used to recall autobiographical memories in depressed and non-depressed participants, with a view to determining whether depressed participants exhibited truncated search strategies. Methods: Thirteen depressed and an equal number of non-depressed participants retrieved 15 memories each, in response to 15 commonly used cue words. Participants reported the first memory that entered in their mind. All memory descriptions were recorded and later transcribed verbatim for content analysis.Results: Depressed participants retrieved autobiographical memories faster, produced shorter memory descriptions and were less likely to recall positive memories than non-depressed participants. Non-depressed participants were more likely to commence retrieval by accessing lifetime period knowledge followed by general event and event specific knowledge, whereas depressed participants showed a tendency to terminate retrieval at the general event level. Conclusions: It is concluded that depressed participants do adhere to the same hierarchical search strategy as non-depressed participants when retrieving specific autobiographical memories, but that they terminate their search early, resulting in overgeneral memories

Comparative cytogenetic analysis of two grasshopper species of the tribe Abracrini (Ommatolampinae, Acrididae)

The grasshopper species Orthoscapheus rufipes and Eujivarus fusiformis were analyzed using several cytogenetic techniques. The karyotype of O. rufipes, described here for the first time, had a diploid number of 2n = 23, whereas E. fusiformis had a karyotype with 2n = 21. The two species showed the same mechanism of sex determination (XO type) but differed in chromosome morphology. Pericentromeric blocks of constitutive heterochromatin (CH) were detected in the chromosome complement of both species. CMA3/DA/DAPI staining revealed CMA3-positive blocks in CH regions in four autosomal bivalents of O. rufipes and in two of E. fusiformis. The location of active NORs differed between the two species, occurring in bivalents M6 and S9 of O. rufipes and M6 and M7 of E. fusiformsi. The rDNA sites revealed by FISH coincided with the number and position of the active NORs detected by AgNO3 staining. The variability in chromosomal markers accounted for the karyotype differentiation observed in the tribe Abracrini

Karyology of the Atlantic forest rodent Juliomys (Cricetidae): A new karyotype from southern Brazil

Juliomys is a small rodent from the family Cricetidae which inhabits the Atlantic forest and forests from Argentina to eastern Brazil. The three species recognized so far have different karyotypes. In this paper, we describe a new karyotype with 2n = 32, FN = 48 found in Juliomys specimens from a high-altitude area in the Atlantic forest of southern Brazil. The karyotype was analyzed after G- and C-banding and silver staining of the nucleolus organizer regions (Ag-NOR) and its G-banding patterns were compared with those of the newly described species Juliomys ossitenuis (2n = 20, FN = 36). The 2n = 32 karyomorph presented peculiar features and was very different from those of the other species of the genus: J. pictipes (2n = 36, FN = 34), J. rimofrons (2n = 20, FN = 34) and J. ossitenuis (2n = 20, FN = 36). Differences were mostly due to centric and tandem fusions, pericentric inversion and loss of heterochromatin. The karyotype represents a powerful tool to differentiate Juliomys species and our data suggest that the karyotype described herein belongs to a new species

New occurrence of B chromosomes in Partamonahelleri (Friese, 1900) (Hymenoptera, Meliponini)

Cytogenetic analyses of the stingless bee Partamona helleri collected in the state of Bahia, Northeast Brazil revealed the chromosome numbers n = 18 in the haploid males and 2n = 35 in the diploid females. All karyotypes displayed one large acrocentric B chromosome, which differs from the minute B chromosomes previously described in the populations from southeastern Brazil. Giemsa staining, C-banding and DAPI/CMA3 fluorochrome staining also revealed a remarkable interpopulational divergence regarding both the regular karyotype and the B chromosomes. The B chromosomes found in the samples from Jequié, Bahia, were entirely heterochromatic, while those found in Cravolândia, Bahia, displayed a euchromatic portion at the telomeric end of the long arm. CMA 3 labeling sites varied from seven to eight between the two localities in Bahia, due to the presence of an extra GC-rich block in the karyotype of the samples from Jequié. This is the first report of a large B chromosome in P. helleri and reveals the occurrence of a geographic differentiation within this species