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Integrated spatial electron populations in molecules: The electron projection function.

A "projection function," P(x,z), is defined as the partial integral of the molecular electron density, rho(x,y,z), over the region -infinity < y < +infinity. The projection provides a three-dimensional representation of molecular electron distributions. Chemically useful information can be discerned from graphical displays in either perspective plot or contour format. Numerical integration of the function gives the integrated spatial electron population for any region of interest. The use of the projection function and difference functions is exemplified by application to acetaldehyde.

Journal Article↗

An assessment of the accuracy of a regional economic-demographic projection model.

A large number of regional economic-demographic projection models have been developed but their accuracy has seldom been evaluated. This article examines the accuracy of one such model in projecting total populations for 1980, using 1970 base data, for 106 counties and 553 places in two states. Comparisons of the model's projections to 1980 Census counts reveal mean percentage absolute differences of 10 percent for counties and 14 percent for places. In addition, the model's accuracy was comparable to that for alternative projection systems. When projections for places of less than 1,000 are excluded, differences are substantially reduced. Economic-demographic models appear to be quite useful and deserve further attention.

Demography↗

Axonal connections of the medial magnocellular nucleus of the anterior neostriatum in zebra finches.

The medial magnocellular nucleus of the anterior neostriatum (mMAN) is a small cortical nucleus which was previously identified as a component of the neural circuitry controlling vocal behavior in songbirds based on its efferent connection to the High Vocal Center (HVC), a major song control nucleus (Nottebohm et al. [1982] J. Comp. Neurol. 207:344-357; Bottjer et al. [1989] J. Comp. Neurol. 279:312-326). We have conducted tract tracing experiments (using wheat-germ agglutinin-horseradish peroxidase (WGA-HRP), the carbocyanine dye DiI, and biocytin) to determine the complete pattern of afferent and efferent connections of mMAN in adult male zebra finches. We confirmed the existence of an efferent projection from mMAN to HVC and discovered a novel projection to the region medial to caudal HVC called paraHVC (pHVC). Injections of retrograde tracers into mMAN showed that afferent input to mMAN originates from the dorsomedial nucleus of the posterior thalamus (DMP). Injections of DiI into DMP produced anterograde label over mMAN, thus confirming the DMP-to-mMAN projection. Interestingly, this anterograde label extended beyond the region of mMAN defined by HVC-projecting neurons into the immediately surrounding cortex. This extended terminal field of DMP efferents indicates that mMAN encompasses a core population of projection neurons surrounded by a shell of non-HVC-projecting neurons, both of which receive input from the dorsal thalamus. Analysis of retrograde DiI label resulting from DMP injections revealed two major sources of afferent input to DMP originating in regions of the archistriatum and hypothalamus. Inputs to DMP were distributed throughout the dorsal archistriatum and included the area that receives a projection from the parvicellular shell region of the lateral magnocellular nucleus of the anterior neostriatum, a song control nucleus, as well as the dorsal portion of the robust nucleus of the archistriatum, the motor-cortical output of the song control system. The projections from song control regions of the archistriatum to DMP may feed information back into telencephalic song control circuitry via the DMP-->mMAN-->HVC/pHVC pathway. The other source of afferent input to DMP is located in the external cellular stratum of the lateral hypothalamus (SCE). This newly delineated SCE-->DMP-->mMAN-->HVC/pHVC pathway is the first report of a hypothalamic brain region neuroanatomically integrated with song control circuitry. Because hypothalamic brain regions are important for homeostasis and regulating behavior, the trans-synaptic circuitry of mMAN may help to integrate information about the bird's internal state, such as sexual maturation, with song learning and production.

Afferent Pathways↗

A titanium cementless calcar replacement prosthesis in revision surgery of the femur: 13-year experience.

From January 1987 through December 2000, 1,179 cementless calcar prostheses were implanted at the Texas Center for Joint Replacement. The prosthesis is titanium, has proximal circumferential plasma-spray coating, and is designed for proximal bone loading. The average follow-up for the entire series was 6.2 years, and the projected stem survivorship at 13 years is 95.2%. There have been 9 stem revisions for loosening. When mechanical loosening alone is evaluated, the projected stem survivorship is 99%. There have been 56 revisions in the entire series. Prosthetic survivorship for the entire patient population is projected at 93.6% at 13 years. There have been no cases of distal lysis or late loosening. None of the prostheses are classified as loose at this time, and none are classified as stable fibrous fixation.

Adolescent↗

Complications of pacemakers and defibrillators in the elderly.

Within the United States, the elderly population is projected to increase 126% by 2050, making those over the age of 65 the most rapidly growing segment in the population. Permanent pacemakers and defibrillators are important therapies with expanding indications for their use, and older persons constitute the majority of recipients of these devices. Recognizing complications associated with these cardiac devices is essential in caring for patients with them. Complications can be related to the implantation procedure and are most commonly lead dislodgement, pneumothorax, lead perforation, hematoma, and infection. Intrinsic device programming can also result in complications such as pacemaker syndrome, pacemaker-mediated tachycardia, and inappropriate shocks. Extrinsic factors, such as electromagnetic interference and physically manipulating the device, can also result in problems. Recent work suggests that older age, by itself, is not associated with a significant increase in the complication rates from these devices and should not preclude their use.

Aged↗

Cardiovascular diseases in India.

India is undergoing an epidemiological transition and is on the threshold of an epidemic of cardiovascular disease. Cause-specific mortality data indicate that cardiovascular disease is already an important contributor to mortality. Demographic projections suggest a major increase in cardiovascular disease mortality as life expectancy increases and the age structure of the growing population changes. Surveys in urban areas suggest that coronary risk factors are already widespread and that urgent action is needed to prevent a further rise as socioeconomic development proceeds. It is vital to obtain epidemiological data from several regions in order to plan, initiate and monitor public health action.

Adolescent↗

Future changes in the size and composition of the British labour force: a regional projection exercise.

"The main purpose of this study is to develop a methodology for generating parallel projections of regional population and labour force which not only incorporates expected age/sex/marital-status/regional differences in the economic activity rates but at the same time takes account of demographic factors such as fertility, mortality and interregional migration in the overall projections." A model is developed and adapted to project the British regional population and labor force for 1976 and 1981. These forecasts are then evaluated by comparing them with Office of Population Censuses and Surveys forecasts for the same years (SUMMARY IN FRE, GER)

Developed Countries↗

The effectiveness of the Gail model in estimating risk for development of breast cancer in women under 40 years of age.

Epidemiologic studies have provided information on risk factors for breast cancer. Gail and associates identified five risk factors using the Breast Cancer Detection Demonstration Project (BCDDP) population and developed a model to calculate a composite relative risk (RR). This model is commonly used to counsel women regarding their risk for breast cancer and was used by the National Surgical Adjuvant Breast Project (NSABP) for eligibility for the Breast Cancer Prevention Trial. Because the BCDDP population was composed almost entirely of women 40 years of age or older, our purpose was to evaluate the effectiveness of the Gail model in estimating the risk of breast cancer for women under 40 in the clinical setting. The Gail risk factors were assessed for 124 patients under the age of 40 treated for either ductal carcinoma in situ (DCIS) or invasive breast cancer at the Lahey Hitchcock Medical Center between 1983 and 1995. The RR was calculated using the Gail model. For comparison, two cohorts of women under the age of 40 were used: 107 randomly selected patients who underwent a breast biopsy because of a benign condition and 129 nurses from our institution who responded to a questionnaire that included reproductive and family history information as used in the Gail model. The RR calculated was the RR that existed at the time of the surgical consultation for a suspicious breast lesion. The Tarone-Ware method was used to analyze statistical significance of differences between distribution. Contingency tables were analyzed using Miettinen's modification of Fisher's exact test. No differences were found between the median RR for all groups. Only 2 of the 124 patients with breast cancer had a RR of 5 or more (the RR required to enter the Breast Cancer Prevention Trial). The distribution of age at menarche (AGEMEN) was the same for each group. No difference was found for the distribution of age at first live birth (AGEFLB) between those with breast cancer and those with a benign biopsy or the control group. The number of breast biopsies (NBIOPS) was higher in patients with a benign breast biopsy. No difference was found in the distribution of number of first-degree relatives with breast cancer (NUMREL). Overall the Gail model failed to differentiate those women about to have cancer diagnosed from two control populations. The Gail model is not useful in identifying immediate risk of breast cancer in women under 40 and should not be used for that purpose.

Adult↗

Prevalence of open-angle glaucoma among adults in the United States.

OBJECTIVE: To estimate the prevalence and distribution of open-angle glaucoma (OAG) in the United States by age, race/ethnicity, and gender. METHODS: Summary prevalence estimates of OAG were prepared separately for black, Hispanic, and white subjects in 5-year age intervals starting at 40 years. The estimated rates were based on a meta-analysis of recent population-based studies in the United States, Australia, and Europe. These rates were applied to 2000 US census data and to projected US population figures for 2020 to estimate the number of the US population with OAG. RESULTS: The overall prevalence of OAG in the US population 40 years and older is estimated to be 1.86% (95% confidence interval, 1.75%-1.96%), with 1.57 million white and 398 000 black persons affected. After applying race-, age-, and gender-specific rates to the US population as determined in the 2000 US census, we estimated that OAG affects 2.22 million US citizens. Owing to the rapidly aging population, the number with OAG will increase by 50% to 3.36 million in 2020. Black subjects had almost 3 times the age-adjusted prevalence of glaucoma than white subjects. CONCLUSIONS: Open-angle glaucoma affects more than 2 million individuals in the United States. Owing to the rapid aging of the US population, this number will increase to more than 3 million by 2020.

Adult↗

Prevalence of age-related macular degeneration in the United States.

OBJECTIVE: To estimate the prevalence and distribution of age-related macular degeneration (AMD) in the United States by age, race/ethnicity, and gender. METHODS: Summary prevalence estimates of drusen 125 microm or larger, neovascular AMD, and geographic atrophy were prepared separately for black and white persons in 5-year age intervals starting at 40 years. The estimated rates were based on a meta-analysis of recent population-based studies in the United States, Australia, and Europe. These rates were applied to 2000 US Census data and to projected US population figures for 2020 to estimate the number of the US population with drusen and AMD. RESULTS: The overall prevalence of neovascular AMD and/or geographic atrophy in the US population 40 years and older is estimated to be 1.47% (95% confidence interval, 1.38%-1.55%), with 1.75 million citizens having AMD. The prevalence of AMD increased dramatically with age, with more than 15% of the white women older than 80 years having neovascular AMD and/or geographic atrophy. More than 7 million individuals had drusen measuring 125 microm or larger and were, therefore, at substantial risk of developing AMD. Owing to the rapidly aging population, the number of persons having AMD will increase by 50% to 2.95 million in 2020. Age-related macular degeneration was far more prevalent among white than among black persons. CONCLUSION: Age-related macular degeneration affects more than 1.75 million individuals in the United States. Owing to the rapid aging of the US population, this number will increase to almost 3 million by 2020.

Adult↗