High b-value Diffusion-weighted Imaging: A Sensitive Method to Reveal White Matter Changes in Schizophrenia

Background: b-value is the parameter characterizing the intensity of the diffusion weighting during image acquisition. Data acquisition is usually performed with low b value (b~1000 s/mm2). Evidence shows that high b-values (b>2000 s/mm2) are more sensitive to the slow diffusion compartment (SDC) and maybe more sensitive in detecting white matter (WM) anomalies in schizophrenia.Methods: 12 male patients with schizophrenia (mean age 35 +/-3 years) and 16 healthy male controls matched for age were scanned with a low b-value (1000 s/mm2) and a high b-value (4000 s/mm2) protocol. Apparent diffusion coefficient (ADC) is a measure of the average diffusion distance of water molecules per time unit (mm2/s). ADC maps were generated for all individuals. 8 region of interests (frontal and parietal region bilaterally, centrum semi-ovale bilaterally and anterior and posterior corpus callosum) were manually traced blind to diagnosis.Results: ADC measures acquired with high b-value imaging were more sensitive in detecting differences between schizophrenia patients and healthy controls than low b-value imaging with a gain in significance by a factor of 20- 100 times despite the lower image Signal-to-noise ratio (SNR). Increased ADC was identified in patient's WM (p=0.00015) with major contributions from left and right centrum semi-ovale and to a lesser extent right parietal region.Conclusions: Our results may be related to the sensitivity of high b-value imaging to the SDC believed to reflect mainly the intra-axonal and myelin bound water pool. High b-value imaging might be more sensitive and specific to WM anomalies in schizophrenia than low b-value imaging

Effect of soil management on the white grub population and damage in soybean

To evaluate the effect of soil management systems on population of white grubs, (Phyllophaga cuyabana Moser), and on its damage in soybean, experiments were set up under no-tillage and conventional tillage (one disk plow, and a leveling disk harrow) areas. Primary tillage equipment, used in other soil management systems, such as moldboard plow, disk plow, chisel plow and heavy duty disk harrow were also tested. Fluctuation of P. cuyabana population and the extent of its damage to soybean was similar under no-tillage and conventional tillage systems. Results comparing a range of primary tillage equipment showed that it affected soil insect populations differently, depending on the time during the season in which tillage was executed. Larval mortality could mostly be attributed to their exposure to adverse factors, soon after tillage, than to changes in soil conditions. Reduction of white grub population was more evident in plots managed by heavier equipment, such as the moldboard plow. Soil tillage could be one component within the soil pest management system in soybean, however, its use can not be generalized.

The White Cane Magazine, Fall 2013, Vol. 4, no. 3

Quarterly newsletter produced by the Iowa Department of Blind, about the information and activities that are on going in the department.

The White Cane Magazine, Spring 2013, Vol. 4, no. 2

Quarterly newsletter produced by the Iowa Department of Blind, about the information and activities that are on going in the department.

The White Cane Magazine, Winter 2013, Vol. 4, no. 1

Quarterly newsletter produced by the Iowa Department of Blind, about the information and activities that are on going in the department.

Model development for capercaillie (Tetrao urogallus) habitat in the Jura Mountains (Western Switzerland)

Capercaillie, Tetrao urogallus, is a threatened species in central Europe, and Swiss populations declined 40 to 50 % between 1970 and 1985. Capercaillie are sensitive to forest structure, and loss of habitat is a major cause of their decline. Knowledge of habitat characteristics is therefore essential for capercaillie conservation. Here, we present models predicting capercaillie probability of occurrence, based on relevant structural habitat variables. Models were built using multiple logistic regression analyses on capercaillie presence/absence data. Vegetation survey was carried out in July 1999 in a 170-km2 forested area (Jura mountains, canton de Vaud, western Switzerland) inhabited by capercaillie and presence/absence of the species was assessed according to dropping presence/absence. The survey was based on 10-m-radius sample plots each in a 1-km2 forest patch (n = 76 with capercaillie droppings, n = 80 without). A first model included seven out of 27 measured habitat variables and a second model only four. The latter model best represents practical needs. It includes three variables which had a negative impact on capercaillie presence: tree and shrub covers and spruce, Picea excelsa, shrub cover, and one which had a positive effect: bilberry, Vaccinium myrtillus, cover, highlighting that capaercaillie selected open forest with high bilberry abundance. The model can be used to map potential capercaillie habitat distribution and to manage the habitat in favour of capercaillie (protection and adapted forestry practices) in the Swiss Jura mountains.

Body fat distribution in white and black women: different patterns of intraabdominal and subcutaneous abdominal adipose tissue utilization with weight loss.

BACKGROUND: Intraabdominal adipose tissue (IAAT) is the body fat depot most strongly related to disease risk. Weight reduction is advocated for overweight people to reduce total body fat and IAAT, although little is known about the effect of weight loss on abdominal fat distribution in different races. OBJECTIVE: We compared the effects of diet-induced weight loss on changes in abdominal fat distribution in white and black women. DESIGN: We studied 23 white and 23 black women, similar in age and body composition, in the overweight state [mean body mass index (BMI; in kg/m(2)): 28.8] and the normal-weight state (mean BMI: 24.0) and 38 never-overweight control women (mean BMI: 23.4). We measured total body fat by using a 4-compartment model, trunk fat by using dual-energy X-ray absorptiometry, and cross-sectional areas of IAAT (at the fourth and fifth lumbar vertebrae) and subcutaneous abdominal adipose tissue (SAAT) by using computed tomography. RESULTS: Weight loss was similar in white and black women (13.1 and 12.6 kg, respectively), as were losses of total fat, trunk fat, and waist circumference. However, white women lost more IAAT (P < 0.001) and less SAAT (P < 0.03) than did black women. Fat patterns regressed toward those of their respective control groups. Changes in waist circumference correlated with changes in IAAT in white women (r = 0.54, P < 0.05) but not in black women (r = 0.19, NS). CONCLUSIONS: Despite comparable decreases in total and trunk fat, white women lost more IAAT and less SAAT than did black women. Waist circumference was not a suitable surrogate marker for tracking changes in the visceral fat compartment in black women.

Systematic and biogeographic relationships of the Japanese white-toothed shrew (Crocidura dsinezumi)

To assess the zoogeographic and phylogenetic relationships of C. dsinezumi, its systematic position has been investigated through electrophoretic comparisons. These comparisons comprise typical Indomalayan and Palaearctic species, including C. russula, the supposed sister taxon of the Japanese white-toothed shrew. The range of measured genetic distances that separate dsinezumi from the other shrews (Nei's D = 0.232-0.406) is typical for interspecific comparisons among Crocidura taxa. Our results reinforce morphologic considerations that suggest C. dsinezumi be treated as a valid species. Phylogenetic relationships deduced from a cladistic treatment of allozyme data refute the possibility that the western Palaearctic C. russula is the sister taxon of C. dsinezumi. Zoogeographic interpretation of the genetic results indicates that the Southeast Asian representatives constitute a clade distinct from one that includes the Palaearctic species. However, C. dsinezumi is difficult to assign to either clade due to many intermediate or plesiomorphic electrophoretic characters. Unlike the major karyologic and biochemical separation that divides Afrotropical and Palaearctic species, the subdivision between Palaearctic and Indomalayan Crocidura is not correlated with any trend in karyotypic evolution. It also is shown that the Eurasiatic species of Crocidura possessing 2n = 40 chromosomes (including C. dsinezumi) do not represent a particular clade, but probably share a plesiomorphic character. Further analysis of other Indian or Asiatic species is needed to test whether the Palaearctic versus Indomalayan separation is due to real zoogeographic barriers or whether it is the result of limited samples.

Geographic variation of the greater white-toothed shrew (Crocidura russula Hermann, 1780 Mammalia, Soricidae)

A multivariate morphometric study of the Greater white-toothed shrew (C. russula) throughout its Palearctic range was carried out to search for patterns of geographic variation within the species boundary. Burnaby's and multiple group principal component analysis allowed the adjustment of raw data with respect to within-sample allometric variation. Multivariate 'size-free' results show a stepped dine with the phenotypical trait reduction and shape change from the eastern to the western Maghreb. Pleistocene fossil mandibles proved to have low phenetic distances with eastern populations (Tunisia, east Algeria) and it is argued that their character set is the primitive condition. The ancestral Mid-Pleistocene shrews lived in a relatively more humid climate. Gee-climatic changes in the north African range during the Quaternary provoked phenetic variation of C. russula and, it can be argued, evolution of the modern western C.r. yebalensis. A historical process can thus be assumed as the main cause of this categorical variation, by segmentation of the species range due to gee-climatic events. Morphometric discontinuity within the C. russula Maghreb range is shown to be congruent with karyological and biochemical studies. Moroccan and Tunisian shrews differ, for example, in NFa chromosomes and electrophoretical traits. A stasipatric process should be invoked to explain categorical variation in the Maghreb range. Colonization and divergence of insular populations results in more or less differentiated geographic races. The populations of Ibiza and Pantelleria are close to the species threshold (Nei's D greater than or equal to 0.1). The process of speciation undergone by the Greater white-toothed shrew results in a complex pattern of geographic variation, including both allopatric and non-allopatric modes.

Fecundity versus offspring size in the greater white-toothed shrew Crocidura russula

1. The relationships between female body mass (WWal)i, tter size (m), juvenile growth rate (G) and mass at weaning (W20) were examined by monitoring natural litters in 29 greater white-toothed shrews, Crocidura russula (Hermann 1780). The trade-offs between m and G or W20 were further investigated by manipulating litter sizes: each of seven females reared four litters of 2, 4, 6 and 8 offspring. 2. Offspring mass at weaning (W20) exhibited a large variance, most of which could be attributed (ANCOVA on manipulated litters) to two effects: a litter-size effect, and a female individual effect, referred to as 'female quality'. 3. Litter size explained 68% of the variance in W20 among manipulated litters (linear regression). The limited milk supply was probably responsible for this effect, because litter size depressed growth rate during the first half of the lactation period (G1), but not during the weaning stage (G2). 4. Among non-manipulated litters, litter size correlated positively with maternal body mass (Wa), so that large females tended to produce small juveniles. This correlation between m and Wa is seen as the result of a body-mass dependence in the cost of raising a litter of a given size, during either pregnancy or lactation. 5. Differences in 'female quality' explained 16% of the variance in W20 among manipulated litters. This factor did not affect GI and may thus relate to differences among offspring of different females in their rates of processing milk and/or external food during late lactation. 6. 'Female quality' was independent of both body mass and litter size: larger females did not produce larger offspring when controlled for litter size, while higher-quality females did not produce larger litters. 7. Our results support the hypothesis that most variance in adult and juvenile body masses is non-genetic, and stems from the trade-off between litter size and offspring size.

Epidemiology of Masked and White-Coat Hypertension: The Family-Based SKIPOGH Study.

OBJECTIVE: We investigated factors associated with masked and white-coat hypertension in a Swiss population-based sample. METHODS: The Swiss Kidney Project on Genes in Hypertension is a family-based cross-sectional study. Office and 24-hour ambulatory blood pressure were measured using validated devices. Masked hypertension was defined as office blood pressure<140/90 mmHg and daytime ambulatory blood pressure≥135/85 mmHg. White-coat hypertension was defined as office blood pressure≥140/90 mmHg and daytime ambulatory blood pressure<135/85 mmHg. Mixed-effect logistic regression was used to examine the relationship of masked and white-coat hypertension with associated factors, while taking familial correlations into account. High-normal office blood pressure was defined as systolic/diastolic blood pressure within the 130-139/85-89 mmHg range. RESULTS: Among the 652 participants included in this analysis, 51% were female. Mean age (±SD) was 48 (±18) years. The proportion of participants with masked and white coat hypertension was respectively 15.8% and 2.6%. Masked hypertension was associated with age (odds ratio (OR) = 1.02, p = 0.012), high-normal office blood pressure (OR = 6.68, p<0.001), and obesity (OR = 3.63, p = 0.001). White-coat hypertension was significantly associated with age (OR = 1.07, p<0.001) but not with education, family history of hypertension, or physical activity. CONCLUSIONS: Our findings suggest that physicians should consider ambulatory blood pressure monitoring for older individuals with high-normal office blood pressure and/or who are obese.