Stimulation of Sertoli cell proliferation: defining the response interval to an inhibitor of estrogen synthesis in the boar

Sertoli cell proliferation occurs in two major waves after birth, one neonatally and another prepubertally, each contributing to final testicular size and sperm production. However, little is known about the regulation of either wave. We have previously shown that letrozole, an inhibitor of estrogen synthesis, increases Sertoli cell number and testicular size at sexual maturity in boars. These studies were conducted to determine whether letrozole affects the first or second proliferative wave. Boars were treated with letrozole during the first wave (treatment at 1, 3, and 5 weeks), less frequently (1 week of age only, or 1 and 5 weeks), on postnatal day 1, or during the second wave (weeks 11-16). Sertoli cells were enumerated in testes and estrogen concentrations were evaluated in serum and testes. Compared with vehicle controls, letrozole reduced estrogen in boars treated at weeks 1 and 5 or 1, 3, and 5, on postnatal day 1, or prepubertally. However, Sertoli cell numbers were increased only in boars treated at 1, 3, and 5 weeks of age. Neither perinatal (1 day old) nor prepubertal letrozole treatment affected Sertoli cell numbers. Hence, Sertoli cell proliferation was sensitive to letrozole only if letrozole was administered throughout the first wave, even though estrogen synthesis was effectively inhibited at all ages. These data indicate that the neonatal but not the prepubertal window of Sertoli cell proliferation is sensitive to an inhibitor of estrogen synthesis; this suggests that these two waves are differently regulated.     

Process dissociation, single-process theories, and recognition memory.

According to the assumptions of L. L. Jacoby's (1991) process dissociation method, performance in recognition memory is determined by the combination of an unconscious familiarity process and a conscious intentional recollection process. The process dissociation method is used to produce estimates of the contributions of the 2 components to recognition performance. This article investigates whether the method provides the correct estimates of components if performance actually depends on only a single process or on 2 processes different from those assumed by the method. The SAM model (G. Gillund and R. M. Shiffrin, 1984) was used to produce simulated data based on a single process. Variants of SAM with 2 processes and R. C. Atkinson and J. F. Juola's (1973) 2-process model were used to produce data based on 2 processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mixture Experiment Techniques for Reducing the Number of Components Applied for Modeling Waste Glass Sodium Release

Statistical mixture experiment techniques were applied to a waste glass data set to investigate the effects of the glass components on Product Consistency Test (PCT) sodium release (NR) and to develop a model for PCT NR as a function of the component proportions. The mixture experiment techniques indicate that the waste glass system can be reduced from nine to four components for purposes of modeling PCT NR. Empirical mixture models containing four first-order terms and one or two second-order terms fit the data quite well, and can be used to predict the NR of any glass composition in the model domain. The mixture experiment techniques produce a better model in less time than required by another approach.     

Telecare Call Centre Work and Ageing in Place

We report findings from a study of call centre staff working to deliver a telecare service designed to enable older people to ‘age in place’. We show the steps they routinely take to produce a care system on behalf of their clients and their families that is both workable within the constraints of available resources and fit-for-purpose. In doing so, we have seen how call centre staff share with one another their experiences and solutions to problems, carry out liaison work with networks of lay carers, and generally act as the ‘glue’ providing the all-important link between otherwise fragmented services. We conclude with some thoughts on the significant technical and organizational challenges if the ‘ageing in place’ vision is to be realized in a practical, secure, dependable and cost-effective way.     

Browsing the environment with the SNAP&TELL wearable computer system

This paper provides an overview of a multi-modal wearable computer system, SNAP&TELL. The system performs real-time gesture tracking, combined with audio-based control commands, in order to recognize objects in an environment, including outdoor landmarks. The system uses a single camera to capture images, which are then processed to perform color segmentation, fingertip shape analysis, robust tracking, and invariant object recognition, in order to quickly identify the objects encircled and SNAPped by the user’s pointing gesture. In addition, the system returns an audio narration, TELLing the user information concerning the object’s classification, historical facts, usage, etc. This system provides enabling technology for the design of intelligent assistants to support “Web-On-The-World” applications, with potential uses such as travel assistance, business advertisement, the design of smart living and working spaces, and pervasive wireless services and internet vehicles. An erratum to this article can be found at An erratum to this article can be found at     

Effect of organizational cues and strategies on good and poor comprehenders' story understanding.

In two experiments, we investigated the influence of organizational cues on story comprehension by 7- to 8-year-old children, matched in age and decoding skills but differing in comprehension ability. In Experiment 1, children read abstract stories with titles and pictures that did or did not integrate story information. Providing integrative cues improved comprehension by poor, but not good comprehenders, but had no effect on verbatim recall. Both skill groups recalled more main ideas than subsidiary ones. In Experiment 2, two new groups read the stories without pictures or titles. Poor comprehenders trained to look for "clue words" to infer main story consequences, implicit in the stories, showed better comprehension than such children given no training. Good comprehenders performed at a uniformly high level regardless of training. The results are discussed in terms of cognitive control required to select and coordinate information in text. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

There's Demand For Recyclate,But Little Supply

When the price of crude oil plunged to $37.63 a barrel early in 2020, it was viewed as another blow to the fledgling recycled plastics market. After all, when used correctly, virgin and recycled plastics deliver the same standards in quality, so why should one pay more? (The price of West Texas Intermediate crude was $55.35/bbl on Jan. 20.)     

Metals and selenium in the liver and bone of three dolphin species from South Australia, 1988-2004

Metal and selenium concentrations (wet weight) were determined in the liver (Cd, Hg, Pb, Zn, Cu and Se) and bone (Pb and Cd) of common dolphins (Delphinus delphis, N=71) and bottlenose dolphins (Tursiops truncatus, N=12, and Tursiops aduncus, N=71) stranded or by-caught in South Australia from 1988 to 2004. Differences in metal burdens existed between species, stranding location, and relative age. T. aduncus had the greatest mean tissue burdens of liver Pb (0.45 mg/kg), Cd (6.45 mg/kg), Hg (475.78 mg/kg), Se (178.85 mg/kg) and Zn (93.88 mg/kg) and bone Pb (2.78 mg/kg), probably reflecting their coastal habitat and benthic prey. Mean Cu was highest in T. truncatus (21.18 mg/kg). Bone Cd was measured only in T. aduncus and averaged 0.05 mg/kg. Stranding location impacted metal burdens. Dolphins from Spencer Gulf had higher mean levels of liver Pb (0.39 mg/kg) while Gulf St Vincent dolphins had greater liver Hg (444.64 mg/kg), liver Se (163.12 mg/kg), and bone Pb (2.85 mg/kg). This may be due to high anthropogenic inputs of Pb and Hg into Spencer Gulf and Gulf St Vincent respectively. Liver Cd, Hg, Se and Pb increased with age in all species while Cu decreased with age, in keeping with previous studies. Se and Hg were positively correlated. The possibility that metallothioneins are driving observed correlations between Zn, Cd, Hg and Cu are discussed. Future research must investigate the toxicological consequences of the metal concentrations reported.