Function suggests nano-structure: electrophysiology supports that granule membranes play dice

Cellular communication depends on membrane fusion mechanisms. SNARE proteins play a fundamental role in all intracellular fusion reactions associated with the life cycle of secretory vesicles, such as vesicle–vesicle and vesicle plasma membrane fusion at the porosome base in the cell plasma membrane. We present growth and elimination (G&E), a birth and death model for the investigation of granule growth, its evoked and spontaneous secretion and their information content. Using a statistical mechanics approach in which SNARE components are viewed as interacting particles, the G&E model provides a simple ‘nano-machine’ of SNARE self-aggregation behind granule growth and secretion. Results from experimental work, mathematical calculations and statistical modelling suggest that for vesicle growth a minimal aggregation of three SNAREs is required, while for the evoked secretion one SNARE is enough. Furthermore, the required number of SNARE aggregates (which varies between cell types and is nearly proportional to the square root of the mean granule diameter) affects and is statistically identifiable from the size distributions of spontaneous and evoked secreted granules. The new statistical mechanics approach to granule fusion is bound to have a significant changing effect on the investigation of the pathophysiology of secretory mechanisms and methodologies for the investigation of secretion.     

Maternal Experience Produces Long-Lasting Behavioral Modifications in the Rat.

From 5 to 22 months of age, cognitive and emotional responses of nulliparous, primiparous, and multiparous rats were assessed using a dry land maze (DLM) and an elevated plus-maze (EPM) at 4-month intervals. Parous rats exhibited improved spatial memory in the probe and competitive versions of the DLM, and more exploration in the EPM and a novel stimulus test relative to nulliparous females. The nulliparous females, however, outperformed parous rats during the DLM visual cue test at 17 months of age. At 23 months, no differences in stressed corticosterone levels or Golgi-stained hippocampal neurons were observed. Thus, cognitive and emotional modifications were observed in parous rats; the neurobiological mechanisms for these enduring effects, however, remain to be identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FEG structures for representation and recognition of 3-D polyhedral objects

The paper proposes a fast O(n ^2.5) recognition algorithm for partially occluded 3D polyhedral objects, where n is the number of the polyhedron vertices.Our approach is based on the generate and test mechanism using the alignment approach as its basic recognition tool. The first stage is to align one face of the unknown polyhedron with one face of one library model (generate). The second stage is a recursive test procedure that checks the matching of the remaining faces. A new structure called FEG—Face Edge Graph is introduced. This structure stores information about the 2D coordinates of each face and the identity of its adjacent faces.A very low complexity is achieved by using a divide and conquer strategy. Instead of trying to recognize the whole object at once, we divide it and conquer (recognize) it face by face. This is done by reducing the recognition problem to generalized subgraph matching problem in which two subgraphs are equal not only when they are isomorphic, but also when they represent the same part of the same object. A special mechanism handles false splitting and false merging of adjacent faces as a result of wrong segmentation.The process lends itself to hierarchical parallel processing in that the matching with each library model may be carried out independently, and also for each model—processing at the pixel level may also be done in parallel.We evaluated our approach with several real range data images as well as some synthetic objects. Four of these cases are reported here.     

Failure criteria for brittle elastic materials

The validity of several known failure initiation criteria at reentrant corners in brittle elastic materials is examined and a simple one is proposed. Their predictions, under mode I stress field, are compared to experimental observations carried out on PMMA (polymer) and Alumina-7%Zirconia (ceramic) V-notched specimens. Because all realistic V-notched reentrant corners are blunt, a detailed experimental procedure has been followed, focusing on specimens with different notch tip radii. It is demonstrated that by assuming a sharp V-notch, some failure criteria predict reasonably well the experimental findings, and that corrections are needed in order for these to take into consideration the realistic radius at the notch tip.     

Owner-Driven Suburban Renewal: Motivations,Risks and Strategies in ‘Knockdown and Rebuild’ Processes in Sydney,Australia

Decisions by individual owners about reinvesting capital in their homes are important drivers of wider processes of suburban renewal. This paper examines the motivations for owners in mostly middle-ring suburbs of Sydney, Australia, to reinvest through ‘knockdown and rebuild’ (KDR). This process—not unique to Australia—involves the wholesale demolition of older detached houses and their replacement with completely new dwellings. Until recently, existing literature on housing reinvestment has focused on practices such as renovations or modifications to existing dwellings. Yet, KDR is becoming increasingly popular and moreover appears to involve a distinctive set of actors, drivers and potential impacts. On the basis of a statistical survey of activity followed up by a questionnaire survey and in-depth interviews, the general scale and attributes of KDR are summarised and then explored to discern the main perceived benefits, risks and types of development scenarios pursued. The results reveal a genuine diversity of motivations and circumstances involved in this latest physical makeover of the traditional Australian suburb.     

Determination of Polyphenols,Flavonoids, and Antioxidant Capacity in Colored Chickpea (Cicer arietinum L.)

ABSTRACT: Dry legumes are staple and potentially functional food, being a good source of polyphenols, flavonoids, and antioxidant activity. The objective of this study was to determine the total polyphenol content (TPC), total flavonoid content (TFC), and their relation with antioxidant capacity in 17 chickpea lines having colored seed coats (black, red, brown, green, rubiginous, gray, yellow, cream, or beige). The seed coat usually contains more than 95% of these compounds. In this study, both TPC and TFC varied significantly among different lines and were highly correlated to antioxidant activity. Colored seeds contained up to 13-, 11-, and 31-fold more TPC, TFC, and antioxidant activity, respectively, than cream- and beige-color seeds. Thus, colored chickpea could be a potentially functional food in addition to its traditional role of providing dietary proteins and dietary fibers.     

The crossover of perceived health between spouses.

The current study examined the crossover of perceived health between spouses and the mediating roles of self-esteem and undermining in this process. Data were collected from a sample of 2,108 couples from the Russian Longitudinal Monitoring survey. Using structural equation modeling, the authors tested a crossover model that incorporated three mechanisms: bidirectional crossover of perceived health between spouses, common stressors (income), and indirect mediated effects (social undermining). The model showed an acceptable fit to the data and provided support for all three-crossover mechanisms. Furthermore, self-esteem mediated the relationship between economic hardship and perceived health. The authors discuss theoretical aspects of the crossover of perceived health and implications of our findings for the design of preventive interventions to help family members cope more effectively with economic hardship. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On Estimating the Uncertainty in the Location of Image Points in 3D Recognition from Match Sets of Different Sizes

Efficient and robust model-based recognition systems need to be able to estimate reliably and quickly the possible locations of other model features in the image when a match of several model points to image points is given. Errors in the sensed data lead to uncertainty in the computed pose of the object, which in turn lead to uncertainty in these positions. We present an efficient and accurate method for estimating these uncertainty regions. Our basic method deals with an initial match of three points. With a small additional computational cost it can be used to compute the uncertainty regions of the projections of many model points using the same match triplet. The basic method is then extended employing statistical methods to estimate uncertainty regions when given initial matches of any size. This is the major practical contribution of the paper because when the number of points in the match increases, the size of the uncertainty region decreases dramatically, which helps to discriminate much better between correct and incorrect matches in model-based recognition algorithms.