588 research outputs found
Variability in the vertical distributions of mesopelagic fishes: effect of body size, season, and sampling strategy on the characterization of diel vertical migration
Diel‌ ‌vertical‌ ‌migration,‌ or DVM, ‌is‌ ‌defined‌ ‌as‌ ‌the‌ large-scale changes in the depth distribution of a species or an assemblage with respect to the time of day. DVM‌ ‌is‌ ‌the‌ ‌largest‌ ‌active movement‌ ‌of‌ ‌biomass‌ on Earth, driven by the need for food balanced against predator avoidance and metabolic constraints. Asynchronous‌ ‌diel‌ ‌vertical‌ ‌migration, in the context of this study,‌ ‌refers‌ ‌to‌ the phenomenon where only a portion of a species’ population migrates upwards at night while others remain at depth. ‌The‌ extent that factors such as temporal variation, ontogenic variation, and methodological variation explain this migratory pattern is the focus of this study.‌ ‌Data for five numerically dominant mesopelagic fishes species (four lanternfishes, Benthosema suborbitale, Ceratoscopelus warmingii, Lampanyctus alatus, and Lepidophanes guentheri, and one bristlemouth, Sigmops elongatus) were analyzed from two extensive deep-pelagic research programs in the Gulf of Mexico.‌ A size-depth relationship, with larger individuals in a population residing deeper during daytime, was clearly apparent for four of the five species examined, and likely applied to the fifth. Two species, L. guentheri and B. suborbitale, were synchronous, or near-synchronous vertical migrators. The remaining three species were asynchronous migrators whose diel migration fidelity appeared tied primarily to size. In the two asynchronously migrating lanternfishes the largest size class migrated daily while the smallest migrated least, while the pattern was opposite in the bristlemouth, S. elongatus. A possible ecological explanation for these patterns is presented based on fluid mechanics theory. Given the importance of diel vertical migrators in the global sequestration of carbon via the biological pump, and the increasing sophistication of individual-based models of carbon flux, quantifying the variability in DVM and AVM behavior is essential, as these values drive the models. Quantifying this variability will greatly enhance the accuracy (and likely precision) of carbon flux models, which are vitally important in a rapidly changing deep ocean subjected to increasing human disturbance
Science in the Learning Gardens: A Study of Motivation, Achievement, and Science Identity in Low-Income Middle Schools
Background: Science in the Learning Gardens (henceforth, SciLG) program was designed to address two well-documented, inter-related educational problems: under-representation in science of students from racial and ethnic minority groups and inadequacies of curriculum and pedagogy to address their cultural and motivational needs. Funded by the National Science Foundation, SciLG is a partnership between Portland Public Schools and Portland State University. The sixth- through eighth-grade SciLG curriculum aligns with Next Generation Science Standards and uses school gardens as the milieu for learning. This provides the context to investigate factors that support success of a diverse student population using the motivational framework of self-determination theory.
Results: This study reports results from 113 students and three science teachers from two low-income urban middle schools participating in SciLG. Longitudinal data collected in spring of sixth grade in 2015 and fall of seventh grade in 2015 for the same set of students included a measure of students’ overall motivational experiences in the garden (that combined their reports of relatedness, competence, autonomy, and engagement and teacher-reports of re-engagement in garden-based learning activities) to predict four science outcomes: engagement, learning, science grades, and science identity. Findings suggest that garden-based activities show promise for supporting students’ engagement and learning in science classes and in fostering students’ interest in pursuing science long-term.
Conclusions: As concern for social justice is growing based on the underachievement of students from minority groups, resurgence of the school garden movement over the last several decades provides an opportunity to tip the scales by engaging students in authentic, real-world learning of science and cultivating their interests in science with holistic garden-based learning. This study highlights the role of students’ views of themselves as competent, related, and autonomous in the garden, as well as their engagement and re-engagement in the garden, as potential pathways by which garden-based science activities can shape science motivation, learning, and academic identity in science. Findings also suggest that the motivational model based on self-determination theory can be useful in identifying some of the “active ingredients”—in pedagogy, curriculum, and social relationships—that engage students in these garden-integrated science learning activities
Repetibilidade dos pesos e ganho de peso do nascimento a desmama de bezerros da raça Nelore.
Repetibilidade do ganho de peso ao nascimento e a desmama
An evaluation of three processing methods and the effect of reduced culture times for faster direct identification of pathogens from BacT/ALERT blood cultures by MALDI-TOF MS
Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) is a fast and reliable method for the identification of bacteria from agar media. Direct identification from positive blood cultures should decrease the time to obtaining the result. In this study, three different processing methods for the rapid direct identification of bacteria from positive blood culture bottles were compared. In total, 101 positive aerobe BacT/ALERT bottles were included in this study. Aliquots from all bottles were used for three bacterial processing methods, i.e. the commercially available Bruker’s MALDI Sepsityper kit, the commercially available Molzym’s MolYsis Basic5 kit and a centrifugation/washing method. In addition, the best method was used to evaluate the possibility of MALDI application after a reduced incubation time of 7 h of Staphylococcus aureus- and Escherichia coli-spiked (1,000, 100 and 10 colony-forming units [CFU]) aerobe BacT/ALERT blood cultures. Sixty-six (65%), 51 (50.5%) and 79 (78%) bottles were identified correctly at the species level when the centrifugation/washing method, MolYsis Basic 5 and Sepsityper were used, respectively. Incorrect identification was obtained in 35 (35%), 50 (49.5%) and 22 (22%) bottles, respectively. Gram-positive cocci were correctly identified in 33/52 (64%) of the cases. However, Gram-negative rods showed a correct identification in 45/47 (96%) of all bottles when the Sepsityper kit was used. Seven hours of pre-incubation of S. aureus- and E. coli-spiked aerobe BacT/ALERT blood cultures never resulted in reliable identification with MALDI-TOF MS. Sepsityper is superior for the direct identification of microorganisms from aerobe BacT/ALERT bottles. Gram-negative pathogens show better results compared to Gram-positive bacteria. Reduced incubation followed by MALDI-TOF MS did not result in faster reliable identification
Faster differentiation of Staphylococcus aureus versus coagulase-negative Staphylococci from blood culture material: a comparison of different bacterial DNA isolation methods
Hábitos alimenticios de los juveniles de cuna aguajĂ, (Mycteroperca microlepis) (Pisces: Serranidae) en el suroeste del Golfo de MĂ©xico
Benign anal lesions, inflammatory bowel disease and risk for high-risk human papillomavirus-positive and -negative anal carcinoma.
A central role in anal carcinogenesis of high-risk types of human papillomaviruses (hrHPV) was recently established, but the possible role of benign anal lesions has not been addressed in hrHPV-positive and -negative anal cancers. As part of a population-based case-control study in Denmark and Sweden, we interviewed 417 case patients (93 men and 324 women) diagnosed during the period 1991-94 with invasive or in situ anal cancer, 534 patients with adenocarcinoma of the rectum and 554 population controls. Anal cancer specimens (n = 388) were tested for HPV by the polymerase chain reaction. Excluding the 5 years immediately before diagnosis, men, but not women, with anal cancer reported a history of haemorrhoids [multivariate odds ratio (OR) 1.8; 95% confidence interval (CI) 1.04-3.2] and unspecific anal irritation (OR 4.5; CI 2.3-8.7) significantly more often than controls. Women with anal cancer did not report a history of benign anal lesions other than anal abscess to any greater extent than controls, but they had used anal suppositories more often (OR 1.5; CI 1.1-2.0). Patients with hrHPV in anal cancer tissue (84%) and those without (16%) reported similar histories of most benign anal lesions, but anal fissure or fistula was more common among hrHPV-positive cases. Ulcerative colitis and Crohn's disease, reported by <1% of study participants, were not associated with anal cancer risk. The higher proportion of hrHPV-positive anal cancers among case patients with anal fissure or fistula suggests that such mucosal lesions may provide direct viral access to basal epithelial layers. Since risk associations with benign anal lesions in men may be confounded by unreported sexual behaviour, and since risk associations in women were generally negative, it seems unlikely that benign anal lesions act as promoters in hrHPV-associated anal carcinogenesis. Moreover, benign anal lesions appear not to be linked to an alternative, hrHPV-unassociated causal pathway to anal cancer. Ulcerative colitis and Crohn's disease were not supported as causal factors for anal cancer
Analysis of MHC class I and II expression in relation to presence of HPV genotypes in premalignant and malignant cervical lesions.
Cervical intraepithelial neoplasia (CIN) grades I to III lesions (n = 94) and squamous cell carcinomas of the uterine cervix (n = 27) were analysed for MHC class I and II expression and presence of HPV genotypes. MHC class I and II expression was studied by immunohistochemistry and HPV typing was performed by general primer- and type-specific primer mediated PCR (GP/TS PCR). Both techniques were performed on paraffin embedded tissue sections. Results show disturbed MHC class I heavy chain expression in CIN I to CIN III, as well as in cervical carcinomas. Upregulated MHC class II expression on dysplastic epithelial cells was also found in the different CIN groups and carcinomas. Prevalence of HPV genotypes increased with the severity of the lesion, mainly due to the contribution of the HPV types 16 and 18. No correlation could be established between the presence of specific HPV genotypes and any MHC expression pattern in the different CIN groups or cervical carcinomas. In some cases these data were confirmed by RNA in situ hybridisation showing HPV 16 E7 transcripts in the same dysplastic/neoplastic cells from which MHC status was determined. The results indicate that local differences may exist in the type of cellular immune response to HPV induced lesions
On the shape of a small sessile drop and the measurement of contact angle.
Free liquid surfaces in equilibrium are described by the Laplace capillary equation with suitable boundary conditions generally given in terms of the contact angle. By a fortuitous formulation in the axisymmetric case, the second order ordinary differential equation can be reduced to a pair of coupled first order equations. For the case of a small liquid drop, the present formulation allows perturbation solutions to second order to be derived in closed form. Furthermore the solutions obtained can be used to calculate contact angles, if the height and maximum width of the drop is known, the method being equally simple whether the contact angle is less than or greater than 90 ͦ
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