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Melanopsin-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs) form a light-sensitive system separate from rods and cones. Direct light stimulation of ipRGCs can regulate many nonimage-forming visual functions such as photoentrainment of circadian rhythms and pupil responses, and can intensify migraine headache in adults. In mice, ipRGCs are light responsive as early as the day of birth. In contrast, their eyelids do not open until 12-13 d after birth (P12-13), and light signaling from rods and cones does not begin until approximately P10. No physiological or behavioral function is established for ipRGCs in neonates before the onset of rod and cone signaling. Here we report that mouse pups as young as P6 will completely turn away from a light. Light-induced responses of ipRGCs could be readily recorded in retinas of pups younger than P9, and we found no evidence for rod- and cone-mediated visual signaling to the RGCs of these younger mice. These results confirm that negative phototaxis is evident before the onset of rod- and cone-mediated visual signaling, and well before the onset of image-forming vision. Negative phototaxis was absent in mice lacking melanopsin. We conclude that light activation of melanopsin ipRGCs is necessary and sufficient for negative phototaxis. These results strongly suggest that light activation of ipRGCs may regulate physiological functions such as sleep/wake cycles in preterm and neonatal infants. intrinsically photosensitive retinal ganglion cells | phototaxis | retina | visual behavior doi/ 10.1073/pnas.1008533107

The long-term response to chronic stress is variable, with some individuals developing maladaptive functioning, although other 'resilient' individuals do not. Stress reduces neurogenesis in the dentate gyms subgranular zone (SGZ), but it is unknown if stress-induced changes in neurogenesis contribute to individual vulnerability. Using a chronic social defeat stress model, we explored whether the susceptibility to stress-induced social avoidance was related to changes in SGZ proliferation and neurogenesis. Immediately after social defeat, stress-exposed mice (irrespective of whether they displayed social avoidance) had fewer proliferating SGZ cells labeled with the S-phase marker BrdU. The decrease was transient, because BrdU cell numbers were normalized 24 h later. The survival of BrdU cells labeled before defeat stress was also not altered. However, 4 weeks later, mice that displayed social avoidance had more surviving dentate gyms neurons. Thus, dentate gyrus neurogenesis is increased after social defeat stress selectively in mice that display persistent social avoidance. Supporting a functional role for adult-generated dentate gyms neurons, ablation of neurogenesis via cranial ray irradiation robustly inhibited social avoidance. These data show that the time window after cessation of stress is a critical period for the establishment of persistent cellular and behavioral responses to stress and that a compensatory enhancement in neurogenesis is related to the long-term individual differences in maladaptive responses to stress. dentate gyrus | nestin-GFP | posttraumatic stress disorder | social defeat | subgranular zone doi/10.1073/pnas.0910072107

The contributions of verbal, visual, and spatial working memory to written language production were investigated. Participants composed definitions for nouns while concurrently performing a task which required updating, storing, and retrieving information coded either verbally, visually, or spatially. The present study extended past findings by showing the linguistic encoding of planned conceptual content makes its largest demand on verbal working memory for both low and high frequency nouns. Kellogg, Olive, and Piolat in 2007 found that concrete nouns place substantial demands on visual working memory when imaging the nouns' referents during planning, whereas abstract nouns make no demand. The current study further showed that this pattern was not an artifact of visual working memory being sensitive to manipulation of just any lexical property of the noun prompts. In contrast to past results, writing made a small but detectible demand on spatial working memory. DOI 10.2466/PMS.110.1.229-244

The study examines the informal trading practice of street vendors in Bogota, Colombia and the campaigns of the city's mayors to address this concern. Vendors were relocated to government-built markets, which provided them with better working conditions but led to declining income. Other details on the city's policy implications are discussed.

We have developed an integrated, multidisciplinary methodology, termed systems pathology, to generate highly accurate predictive tools for complex diseases, using prostate cancer for the prototype. To predict the recurrence of [...]

Metastasis is the major cause of cancer morbidity, but strategies for direct interference with invasion processes are lacking. Dedifferentiated, late-stage tumor cells secrete multiple factors that represent attractive targets for [...]

This article examines the development of family farms of the Kipsigis in western Kenya. The author, providing an ethnography of one families attempt to build a farm, maintains the family farm is a geographical space in which individual, state, and local visions of development intersect with the goal of entering the globalized economy.

Byline: Michael Donovan (1) Author Affiliation: (1) Department of Philosophy, Santa Rosa Junior College, 680 Sonoma Mountain Parkway, Petaluma, CA, 94954, USA Article History: Registration Date: 30/09/2004

Byline: Harry P.W. Kozakewich (1), Antonio R. Perez-Atayde (1), Michael J. Donovan (1), Jonathan A. Fletcher (2), Judy A. Estroff (3), Robert C. Shamberger (4), Lisa Diller (5) Keywords: Key words: congenital neuroblastoma, cystic neuroblastoma, adrenal cyst, newborn, infant Abstract: Cystic neuroblastoma (CN) is an unusual variant of neuroblastoma characterized by a grossly visible cyst(s) and almost always distinctive microcysts on light microscopy. Rarely, CN will appear solid grossly, but microcystification will be present. We examined the clinical, pathologic, and biologic features of 17 cases of CN. The majority of CN had been detected by prenatal ultrasound. The tumors were favorable stage, stroma-poor, but with low or intermediate mitotic-karyorhectic indices and had favorable biologic markers reflected by aneuploidy and by an absence of N-myc amplification and chromosome 1p deletions. However, the high trk expression typically identified in good risk tumors was absent. Although the complete natural history of CN is not fully defined, our experience suggests that some tumors progress in size, whereas others may spontaneously regress or mature. The clinical outcome is excellent, as is expected in localized and stage 4S neuroblastoma in infancy. Author Affiliation: (1) Department of Pathology, Children's Hospital, and Department of Pathology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA , US (2) Department of Pathology, Brigham and Women's Hospital, and Departments of Pediatrics and Pathology, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA , US (3) Department of Radiology, Children's Hospital, and Department of Radiology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA , US (4) Department of Surgery, Children's Hospital, and Department of Surgery, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA , US (5) Department of Medicine, Children's Hospital, Department of Pediatric Oncology, Dana-Farber Cancer Institute, and Department of Pediatrics, Harvard Medical School, 44 Binney Street, Boston, MA 02115, USA , US Article note: Received June 13, 1996 accepted June 19, 1997

We have generated null mutant mice that lack expression of all isoforms encoded by the trkC locus. These mice display a behavioral phenotype characterized by a loss of proprioceptive neurons. Neuronal counts of sensory ganglia in the trkC mutant mice reveal less severe losses than those in NT-3 null mutant mice, strongly suggesting that NT-3, in vivo, may signal through receptors other than trkC. Mice lacking either NT-3 or all trkC receptor isoforms die in the early postnatal period. Histological examination of trkC-deficient mice reveals severe cardiac defects such as atrial and ventricular septal defects, and valvular defects including pulmonic stenosis. Formation of these structures during development is dependent on cardiac neural crest function. The similarities in cardiac defects observed in the trkC and NT-3 null mutant mice indicate that the trkC receptor mediates most NT-3 effects on the cardiac neural crest.

Vertebrate kidney development involves a series of complex interactions between the ureteric bud and undifferentiated mesenchyme resulting in the production of the nephron unit. These interactions are thought to be dependent on a variety of locally derived soluble factors, including peptide growth factors and their receptors. We have extensively analyzed the neurotrophins (NT) and their receptors during human kidney development. The neurotrophin receptors p75 and trk were both present within cells of early glomerular/tubular structures but absent from uninduced mesenchyme. Later in organo-genesis, the NTs NT-3 and BDNF colocalized with their respective receptors in differentiated tubules. These findings suggested that the NT:receptor complex was not involved in the early inductive events of renal development but was responsible for postinductive tubulogenesis and epithelial integrity. In situ hybridization confirmed selective localization for the expression of trk B and trk C receptors and Western blot identified a full-length (kinase-active) trk receptor during human kidney development.

Narratives of the Kipsigis of rural Kenya provide insights into their experiences of structural and geographical change in the Ndaraweta sublocation. These narratives revolve around the impact of the development of capitalist family farms from a state of shifting cultivation. The immigration of Kipkasare settlers to the sublocation brought changes in the wider political culture and economy of the Kipsigis. The Kipsigis are able to relate to global and regional events with the help of these stories of transformation of persons, history, and place.

A novel route for the facile preparation of (co) polymer-stabilized transition metal nanoparticles, via the 'grafting-to' approach is described. The (co) polymers employed as stabilizers are synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization in aqueous media.

Issues are presented concerning the role of science teachers in encouraging college students to analyze new concepts and question scientific accounts. The use of the disequilibrium technique to teach students is discussed.

Science teachers should make use of fictional, dramatic and poetic information sources in classroom studies. Text books and reference sources, which can be dry and uninteresting, should be used alongside more exciting information sources when appropriate. Students can compare and contrast a variety of concepts in relation to scientific sources that are based on fact.

Calls for the upgrading of science education have led to the formulation of standards to be adhered to in the training of science teachers. For instance, the National Science Teachers Assn points out the need for teachers to have a genuine understanding of the essence of science. It underscored the observation that both teachers and students are unable to accurately distinguish scientific theories from natural laws. The latter statement, however, unfairly criticizes science teachers for a shortcoming that is also exhibited by authors of college science textbooks.

Science teachers should realize they are partially to blame for students' failure to think critically. Most students simply memorize statements and concepts without understanding the relationships between them. However, teachers can force students to think critically by designing tests that require more than the memorization of terms. Ideas for such tests can be obtained from standardized examinations such as as the LSAT, GRE and MCAT.

College administrators are increasingly evaluating the quality of their courses and institutions according to various measures of success. These measures include nationally-based examination results, graduate jobs and graduate salaries. This sort of validation is based on the perception that students are products rather than people. Education should enable students to develop their understanding of life, not process them for some predetermined outcome. Students are free to use their learning opportunities as they wish, so course evaluation should be based on course content, not students.

The field of biology uses plenty of terms that are inappropriate or inaccurate. Some words, such as secretion or cortical 'granules,' have become outmoded since new technologies have revealed new characteristics of the objects that they refer to. Other terms, such as trypsin and pepsin, are appropriate, but they do not conform to the rules of nomenclature implemented after names can no longer be altered because they have become too widely used. There are also other terms that are totally inappropriate, such as 'dominant' and 'recessive' because of the different meanings attached to them.

The newest president of the Society for College Science Teachers (SCST) and current writer responsible for the SCST column section in the Journal of College Science College Teaching publication opines that the column's true purpose is to provide a common ground for science instructors at all colleges and universities to exchange views on relevant issues. The columnist therefore welcomes encourages guest writers and responses to his articles, which will reprove several prevalent procedures in science education.