Absence Of Significant Correlation Research Articles

Investigating the impact of the COVID-19 pandemic on the cognitive dissonance of adolescents

The COVID-19 pandemic has had a profound impact on adolescent mental health, leading to the formation of distinct perspectives on the pandemic. These perspectives often give rise to internal conflict within individuals. In this study, we aimed to examine the variability and complexity of these perspectives through the lens of cognitive dissonance, the psychological discomfort one feels when their external behaviors do not align with their internal beliefs. We collected the data through self-reported surveys, which assessed participant (teenagers aged 13-18) agreement with various opinions and statements related to the pandemic. The survey encompassed five main categories, or “batteries”: general COVID-19, vaccination, masking, government/authority, and school. We had three primary hypotheses: 1) adolescents would experience dissonance, 2) adolescents would consider different aspects of the pandemic independently from each other and hence cross-battery scores would be statistically different, and 3) both gender and vaccination status would have an effect on dissonance levels. Our results corroborated the conjecture that study participants experienced dissonance, as three out of the five batteries displayed mean scores indicative of dissonance. Furthermore, as evidenced by the absence of significant correlation (no r constant was greater than 0.341) and the presence of statistically significant differences between individual batteries (with seven out of nine comparisons having p-values <0.05), we proved our second hypothesis true. Lastly, through a linear regression test, we identified gender, albeit not vaccination status, to have a considerable effect on adolescents' dissonance scores.

Precipitation as a key control on erosion rates in the tectonically inactive northeastern Sonoran Desert, central Arizona, USA

ABSTRACT Langbein and Schumm (1958) connected precipitation to erosion in a right-skewed curve used in earth science textbooks for over six decades, where denudation increases with precipitation on the arid/semiarid limb and decreases in humid regions. Development of the catchment-averaged 10Be denudation method a quarter-century ago led geomorphologists to evaluate this hypothesis using data not influenced by the Anthropocene, with mixed findings. The Sonoran Desert in Arizona, USA, is optimal for investigating the longstanding hypothesis of increased erosion from arid to semiarid climates due to: (i) the modern orographic effect aligning elevated precipitation with altitude, mirroring Neotoma packrat midden paleoecology research for the Holocene and late Pleistocene; (ii) the region has been tectonically quiet for the residence times of analyzed 10Be ranging from ca. 8,000-110,000 years. Our significant finding echoes Langbein and Schumm's work, revealing heightened erosion along an elevation-precipitation gradient from arid to semiarid conditions. Notably, the significance of precipitation-elevation contrasts with the absence of significant correlation between 10Be denudation and attributes like slope, drainage area, relief, or landform type (e.g., alluvial fan, pediment, mountain watershed). Modern faunalturbation, increasing along this gradient, exposes more ground to rainsplash and overland flow at higher elevations, adding complexity to these results. Further insights unveil that (i) catchments in areas with substantial Quaternary base level reduction imitate tectonic effects, tripling 10Be denudation rates; (ii) basaltic boulders and cobbles yield an armoring influence; (iii) historical erosion acceleration due to urbanization and wildfires insignificantly affects 10Be denudation rates in the Sonoran Desert; and (iv) minute desert catchments yield anomalous erosion rates.

Estimativa da ploidia e pré-seleção de autotetraploides de bananeira após indução da poliploidia in vitro

ABSTRACT This study aimed to evaluate the efficiency of the parameters fresh leaf mass and stomatal density in the estimation of ploidy and pre-selection of putative banana autotetraploids. Young plants of the diploid cultivar Ouro (AA), previously subjected to in vitro polyploidization with the antimitotic amiprofos-methyl - APM (0, 10, 20, 30, 40, and 60 µM L-1) and colchicine (2.5 mM L-1) were evaluated for survival, height, number of leaves, pseudostem diameter, leaf disc fresh mass, and stomatal density. Ploidy was determined by flow cytometry in a random sample of 200 plants to find the relationship between the genomic content and the analyzed variables. Spearman’s correlation analysis showed a strong correlation (0.84**) between leaf disc fresh mass and tetraploid plants, as well as an absence of significant correlation between stomatal density and ploidy levels. Thus, the pre-selection of plants was carried out using a reference value of leaf disc fresh mass and resulted in 688 plants pre-selected as putative tetraploids. Among them, 318 were confirmed as tetraploids, 291 as diploids, and 79 as mixoploids after flow cytometry analysis. The pre-selection efficiency was 46.2% of tetraploid plants from the total pre-selected. The results indicate that the use of leaf disc fresh mass is a simple, practical, and promising method to estimate ploidy when a high number of plants is obtained in in vitro banana polyploidization studies, reducing the total number of plants to have confirmed ploidy.

ROAD TRANSPORT SYSTEM IN THE RURAL AREAS AND FOOD SECURITY IN NIGERIA: A CASE OF AKINYELE LOCAL GOVERNMENT OF OYO STATE, NIGERIA

Food production in Nigeria depends largely on subsistence farmers in the rural areas, where inefficient transport system remains a serious challenge and threat to food security in the country. This paper examines the effect of road transport system in the rural areas on food security in Akinyele Local Government Area of Oyo State, Nigeria. The study adopts a descriptive analysis, Multicollinearity and Cronbach Alpha Reliability tests as well as regression analysis on the primary data. Findings from the study reveal through the multicollinearity test, absence of significant correlation among the independent variables and the Cronbach Alpha confirms internal consistency of the variables. Furthermore, the regression analysis indicates that transportation infrastructure has a positive and statistically significant effect on food security. More so, rural development and road network show positive significant effect on food security. Meanwhile, Market infrastructure and Security issues are not statistically significant to explain variations in food security. The paper therefore, recommends that governments should extend efficient road transport to the rural areas to facilitate the movement of agricultural produce from the village to the market and the industries. This will help to reduce wastes resulting from damage of farm produce due to the long distance to the city.

A Comparative Immunohistochemical Study of Expression of Syndecan-1 (CD138) and Podoplanin in Keratocystic Odontogenic Tumor, Orthokeratinized Odontogenic Cyst and Dentigerous Cyst

Background: Odontogenic lesions can bring about diagnostic challenges due to overlapping histology among pathologists. Thus, there are few tumor markers that provide accurate diagnosis. Syndecan-1 (CD-138) and podoplanin (PDPN) are proteoglycans that have been described as substantial diagnostic and prognostic markers in various odontogenic lesions. Aim: This study aims to evaluate and compare the immunohistochemical expression of syndecan-1 (CD-138) and podoplanin in keratocystic odontogenic tumor, orthokeratinized odontogenic cyst (OOC), and dentigerous cyst (DC). Materials and Methods: The formalin-fixed paraffin-embedded tissue blocks of KCOT, OOC, and DCs were retrieved form the archives of department. Three sections each of 3 μm thickness were made using a rotary microtome and they were stained with syndecan-1 (CD-138) and podoplanin (PDPN) using immunohistochemical methods and standard hematoxylin and eosin stain. Results: Immunohistochemical expression of syndecan-1in KCOT was found to be weakly to moderately positive in 6 cases with 2 cases exhibiting positive expression. In OOC, 3 cases displayed negative expression-1 whereas 7 cases were weakly to moderately positive. Immunohistochemical expression of podoplanin in KCOT was observed to be weakly to moderately positive in 4 cases with 5 cases exhibiting strongly positive expression. In OOC, 3 cases displayed negative immunohistochemical expression for podoplanin and 4 cases were strongly positive. Immunoreactivity for podoplanin in DC was negative in 3 cases whereas 5 cases were weakly to moderately positive. Conclusion: The absence of significant correlation between expression of syndecan-1 and podoplanin reinforces the exact role of these proteins in the differentiation of odontogenic lesions which need to be elucidated further.

Identification of a new spectral signature at 3 [formula omitted]m over martian northern high latitudes: Implications for surface composition

Mars northern polar latitudes are known to harbor an enhanced 3 μm spectral signature when observed from orbit. This may indicate a greater amount of surface adsorbed or bound water, although it has not yet been possible to easily reconcile orbital observations with ground measurements by Phoenix. Here we re-analyzed OMEGA/Mars Express observations acquired during the Northern summer to further characterize this 3 μm absorption band increase. We identify the presence of a new specific spectral signature composed of an additional narrow absorption feature centered at 3.03 μm coupled with an absorption at λ≥3.8μm. This signature is homogeneously distributed over a high-albedo open ring surrounding the circumpolar low-albedo terrains between ∼68°N and 76°N and ∼0°E and 270°E. This location includes the Phoenix landing site. This feature shows no time variability and can be confidently attributed to a seasonally stable surface component. All together, the stability, spectral shape and absence of significant correlation with other signatures in the 1–2.5 μm range discard interpretations relying on water ice or easily exchangeable adsorbed water. Sulfates, notably anhydrite, provide interesting comparisons to several sections of the spectrum. Analogies with Earth samples also show that the spectral signature could result from a latitudinal modification of the hydration state and/or grains size of salts contaminants. While the exact full spectral shape cannot be easily reproduced, plausible explanations to this observation seem to involve geologically recent water alteration at high northern latitudes.

Relationship Between Voluntary Attendance and Academic Performance in First Year Medical Students

The objective of this study was to assess the effects of voluntary attendance at nonmandatory sessions on academic success in the undergraduate medical school setting before and after COVID-19 curriculum changes. First year medical students enrolled at UCF College of Medicine gave informed consent to participate in the study in August 2019, prior to the start of their M1 year. Four biomedical sciences courses occurred during the timeframe of the study. Classes 1 and 2, plus the first half of Class 3, were delivered as conventional face-to-face classes. In March 2020, all lessons were moved online in response to the COVID-19 pandemic, which included the second half of Class 3 and all of Class 4. For the face-to-face encounters, attendance was recorded using the Bluetooth enabled smartphone app, SpotterEDU and the percent of total days attended during each course was correlated with the corresponding multiple-choice final examination score for each participant. To assess the impact of losing the opportunity to attend during Classes 3 and 4, a group of primarily “attenders” was identified as those students who attended ≥ 50% of the nonmandatory sessions in Class 3, prior to the suspension of regular classes. ANOVA was used to assess whether exam scores differed between Classes 1-4 for this group. Eighty-two students participated in the study. The average face-to-face attendance rates before COVID19 were as follows; Class 1: 69% days, Class 2: 41% days, Class 3: 28% days attended. A linear regression analysis for final exam score versus percent of days attended demonstrated no significant association between attendance and performance (Class 1: R2=0.06, Class 2: R2= 0.00, Class 3:R2= 0.01; N=82). During the 3rd course, 22 of the 82 participants attended ≥ 50% of nonmandatory sessions. For 21 completed exam records, no significant difference in performance was observed post-COVID-19 (F=3.1, p=0.06). The mean scores for the attender group were as follows; Class 1 89.7% (SD 4.0), Class 2 87.7% (SD 4.8), Class 3 90.8% (SD 5.2), Class 4 90.9% (SD 6.8). The absence of significant correlation between face-to-face attendance and examinations scores, and the lack of impact on performance when classes were moved online, argues that classroom attendance is not an important mediator of success on knowledge-based multiple-choice examinations.

THE CORRELATION BETWEEN THE DURATION OF FETAL EXTRACTION DURING ELECTIVE CESAREAN SECTION AND DEVELOPMENT OF TRANSIENT TACHYPNEA OF THE NEWBORN

Background: A cesarean section (C.S) is usually performed when a vaginal delivery would put the baby's or mother's life or health at risk. Delivery by cesarean section is one of the major risk factors for transient tachypnea of the new born (TTN). Objective: The current study was designed to assess the relation between the duration of fetal extraction during cesarean section and Apgar score. Patients and methods: Fifty pregnant women were included in the study fulfilling the inclusion and exclusion criteria. Time from incision of skin till clamping of the cord and time from incision of the uterus till clamping of the cord were recorded. Apgar score at 1 and at 5minutes, respiratory rate and weight of neonate were reported and the occurrence of TTN among the studied neonates. Results: No correlation between the duration of fetal extraction and Apgar score recorded at 5 minutes. It was noticed that absence of significant correlation between TTN development and history of previous cesarean section, there is no significant relation between BMI and development of TTN. It was noticed that absence of significant correlation between the time from incision of skin till clamping of the cord (S-C interval) and the development of TTN Also there is no statically significant correlation between development of TTN and between the time from incision of uterus till clamping of the cord (U-C interval). Conclusion: No correlation between the duration of fetal extraction during cesarean section and development of transient tachypnea of the newborn.

THE CORRELATION BETWEEN THE DURATION OF FETAL EXTRACTION DURING ELECTIVE CESAREAN SECTION AND DEVELOPMENT OF TRANSIENT TACHYPNEA OF THE NEWBORN

Background: A cesarean section (C.S) is usually performed when a vaginal delivery would put the baby's or mother's life or health at risk. Delivery by cesarean section is one of the major risk factors for transient tachypnea of the new born (TTN). Objective: The current study was designed to assess the relation between the duration of fetal extraction during cesarean section and Apgar score. Patients and methods: Fifty pregnant women were included in the study fulfilling the inclusion and exclusion criteria. Time from incision of skin till clamping of the cord and time from incision of the uterus till clamping of the cord were recorded. Apgar score at 1 and at 5minutes, respiratory rate and weight of neonate were reported and the occurrence of TTN among the studied neonates. Results: No correlation between the duration of fetal extraction and Apgar score recorded at 5 minutes. It was noticed that absence of significant correlation between TTN development and history of previous cesarean section, there is no significant relation between BMI and development of TTN. It was noticed that absence of significant correlation between the time from incision of skin till clamping of the cord (S-C interval) and the development of TTN Also there is no statically significant correlation between development of TTN and between the time from incision of uterus till clamping of the cord (U-C interval). Conclusion: No correlation between the duration of fetal extraction during cesarean section and development of transient tachypnea of the newborn.

The peculiarities of using and reading of hydrogen breath test results with lactose load in young children and their mothers

Purpose of the work is to evaluate efficacy of using hydrogen breath test with nutritional lactose load among young children and their mothers and correlation of the test results with manifestation of functional gastrointestinal disorders in children. Materials and methods . Hydrogen breath test with nutritional lactose load, genetic marker C (-13910)T of the gene MCM6 investigation by buccal scraping, microbiological investigation of stool were carried out in 32 young children between 1 month and 2 years of age with different manifestations of functional gastrointestinal disorders. HBT was carried out in mothers of investigated children. Results. 18.8 % of children had positive HBT (lactose intolerance – LI), 31.2 % of young children had doubtful result (small intestinal bacterial overgrowth syndrome – SIBO). Positive results of HBT were received in 43.7% of cases, doubtful ones were received in 9.4 % of women among mothers of investigated children. Maximal level of hydrogen in children with LI is 45.5 (40.0–53.0) ppm, it has been fixed on the 180 th (150–180) minute, that is likely later than in adults. Investigation of children intestinal microbiota showed decreasing of bifidobacteria and lactobacteria in 43.8% of cases and increasing of opportunistic flora in 93.8 % against this background including K. pneumoniae – 46.9 %, S. aureus – 53.1%, K. oxytoca – 18.8 %, E. Coli – 31.2 %, E. Faecalis – 6.2 %, E. Cloacae – 6.2 %, Clostridia – 9.4 %, C. freundi – 6.2 %. Almost all children (93.8 %) were carriers of the main allele C with equal relations (in 46.9 %) between the genotypes C/C and C/T and absence of significant correlation with results of HBT according to the investigation of lactase intolerance genetic marker C (-13910)T. Conclusions. The performed investigations have proved that associations of different opportunistic flora including S. aureus and K. pneumoniae on the background of decreasing of lactobacteria (50.0 %) with the high rate of functional diarrhea and intensity of manifestations of regurgitation syndrome, were revealed in many young children with SIBO (80.0 %) and LI (83.3 %). The lack of statistically significant correlations between the results of HBT in children and their mothers, as well as with genetic marker C (-13910) T of the gene MCM6 investigation demonstrates low level of information content of these investigations for the evidence of transient lactose intolerance in young children.

Efikasi Akademik dan Prokrastinasi Akademik Sebagai Prediktor Prestasi Akademik

The purpose of this research is to investigate the relationship between significance or know the academic efficacy and procrastination academic with achievement students academic of project study guidance and counseling, Teaching and Education Faculty University PGRI East Nusa Tenggara. The number of samples used in the study as much as 92 students drawn from population 1180 includes force 2009 as much as much as 102 students 2010 force 205 students, 2011 as much as 368 students, and force as many as 505 2012 student. The sampling technique used is the purposive sampling technique. Tool collecting data using a detailed questionnaire with Likert scale, which consists of a detailed questionnaire for academic procrastination and academic efficacy. While the achievement of student learning is measured based on the CPI. The analysis used in this study is the technique of correlation of Product Moment with the help of SPSS Version 18.0. The first hypothesis test results showed that the relationship between academic procrastination and academic achievement, known (r) correlation coefficient between academic procrastination and academic achievement of 0.015 with p 0.890 > 0.05 negative correlation, direction and with the guidelines of the wear level of significance of 5%, obtained p 0.890 > 0.0.5 then correlation between academic procrastination and academic achievement is declared not significant. The second hypothesis test results showed a relationship between academic efficacy with academic achievement, known coefficient of correlation (r) between academic efficacy and academic achievement -0.004 0.970 > with p 0.05, direction correlation negative and wear guidelines significance level 5%, obtained p 0.970 > 0.05 then correlation between academic efficacy with academic achievement is expressed is not significant. While the third hypothesis test results showed the absence of significant correlation between academic procrastination and academic efficacy simultaneously toward academic achievement with the retrieved R square (coefficient of determination) of 0000, and the coefficient correlation of 0.015 with 0.990 > p 0.05. Further, it is known from the Fcount of 0.010 of Ftable of 3.10, so that H0 is accepted and Ha was rejected.

Hydrographic characteristics and community structure of epipelagic mesozooplankton in the Dongsha (Pratas) Atoll, South China Sea

The relationship between hydrographic features and the community structure of epipelagic mesozooplankton was examined among 10 stations of the water body within the Dongsha (Pratas) Atoll during April (spring), July (summer) and October (autumn) 2011. The hydrographic conditions of the Dongsha Atoll were likely influenced by air temperature and rainfall due to the semi-enclosed topography. Surface water was warm and less saline, particularly in autumn, apparently due to the passage of Typhoon Nalgae. The highest mean (±s.d.) abundance of mesozooplankton was recorded in spring (1204 ± 336individualsm–3) and the lowest was recorded in autumn (45 ± 9individualsm–3). Twenty-six major mesozooplankton groups were observed across the samples collected. Mesozooplankton communities were dominated by calanoid copepods, crab zoea, fish eggs and foraminiferans, which together comprised 86.01% of the total zooplankton catch. The absence of significant correlation between mesozooplankton abundance and chlorophyll-a concentration indicated that the temporal pattern of the mesozooplankton community seems to be more dependent on physical variables than on primary production.

On the assessment of the reproductive capacity of eastern Baltic cod Gadus morhua callarias (Gadidae) by ichthyoplankton data

Annual egg production in eastern Baltic cod Gadus morhua callarias in 1966–2000 has been assessed. A significant relationship between egg production and recruitment, progeny survival index, and 11psu-isohaline depth has been revealed. Comparison of egg production and spawning stock biomass indices has shown the time difference in their maxima and the absence of significant correlation between them. This difference is assumed to be due to an increase in the share of mature individuals that did not participate in spawning in the late 1970s–early 1980s. The determination of potential egg production, taking into account the share of individuals that spawn during the current year, yielded a significant positive relationship between its value and spawning stock biomass.

Study of Seasonal Variation of Melatonin Levels of Iraqi Awassi Ewes

This study was conducted at the Sheep Farm pertaining to the Department of Animal Resources - College of Agriculture - University of Al-Anbar that located at Latitude 33° 20´ N during the period from 1/3/2013 till 22/12/2013. The objective of this study was to investigate the plasma melatonin levels of Iraqi Awassi ewes. Ten Awassi ewes of 2-4 years old and 41-54 kg live body weight were used in this study. Blood samples were collected from each ewe every 3h for 24h during spring equinox (21-22 March). Summer solstice (22-23 June). Autumn equinox (21-22 September) and Winter solstice (21-22 December). The plasma melatonin levels were determined as well as light intensity. Temperature – humidity index (THI) and body temperature at the time of blood collected. The plasma melatonin levels showed a characteristic seasonal variation and the pattern of melatonin secretion of Iraqi Awassi ewes did not subjected to the normal rhythm of melatonin secretion (high at night and low or undetected at the day). The plasma melatonin levels seem to be highly variable among individuals. The absence of significant correlation was observed between light intensity and plasma melatonin levels. THI and plasma melatonin levels as well as between plasma melatonin levels and body temperature. It was concluded from this study that there was a significant difference in melatonin levels between different seasons.

Investigation of relation between visceral and subcutaneous abdominal fat volumes and calcified aortic plaques via multislice computed tomography.

The present study investigated effect of subcutaneous fat volume and abdominal visceral fat volume on aortic atherosclerosis via multislice computed tomography. The present study comprised 424 subjects who underwent non-contrast-enhanced abdominal CT in our clinic between June 2012 and June 2013. Using dedicated software visceral fat volume was calculated for each individual and then subcutaneous fat volume was calculated by subtracting visceral fat volume from total fat volume. By dividing visceral fat volume/subcutaneous fat volume participants were assigned to three groups according to their mean visceral fat volume/subcutaneous fat volume: Group 1 consisted of subjects with visceral fat volume/subcutaneous fat volume lower than 0.48 (Group 1 < 0.48); Group 2 consisted of subjects with visceral fat volume/subcutaneous fat volume equal to or higher than 0.48 and lower than 0.69 (0.48 ≤ Group 2 < 0.69); and Group 3 consisted of subjects with visceral fat volume/subcutaneous fat volume equal to or higher than 0.69 (Group 3 ≥ 0.69). The mean abdominal aortic calcium scores according to Agatston scoring (au) were 136.8 ± 418.7 au in Group 1, 179.9 ± 463 au in Group 2 and 212.2 ± 486.9 in Group 3, respectively. We have demonstrated a significant correlation between visceral fat volume and abdominal aorta atherosclerosis, while there was absence of significant correlation between subcutaneous fat volume and abdominal atherosclerosis.

TARP‐associated AMPA receptors display an increased maximum channel conductance and multiple kinetically distinct open states

Fast excitatory synaptic transmission in the CNS is mediated mainly by AMPA-type glutamate receptors (AMPARs), whose biophysical properties are dramatically modulated by the presence of transmembrane AMPAR regulatory proteins (TARPs). To help construct a kinetic model that will realistically describe native AMPAR/TARP function, we have examined the single-channel properties of homomeric GluA1 AMPARs in combination with the TARPs, γ-2, γ-4 and γ-5. In a saturating concentration of agonist, each of these AMPAR/TARP combinations gave rise to single-channel currents with multiple conductance levels that appeared intrinsic to the receptor-channel complex, and showed long-lived subconductance states. The open time and burst length distributions of the receptor complexes displayed multiple dwell-time components. In the case of γ-2- and γ-4-associated receptors, these distributions included a long-lived component lasting tens of milliseconds that was absent from both GluA1 alone and γ-5-associated receptors. The open time distributions for each conductance level required two dwell-time components, indicating that at each conductance level the channel occupies a minimum of two kinetically distinct open states. We have explored how these data place novel constraints on possible kinetic models of TARP-associated AMPARs that may be used to define AMPAR-mediated synaptic transmission.

Frost-cracking control on catchment denudation rates: Insights from in situ produced 10Be concentrations in stream sediments (Ecrins–Pelvoux massif, French Western Alps)

The potential tectonic and climatic controls on erosion rates in the European Alps and other mountain belts remain strongly debated. We have quantified denudation rates at catchment scales using in situ produced cosmogenic nuclides ( 10Be) in stream sediments, sampled at the outlets of twelve variously sized (27–1072 km 2) catchments of the Ecrins–Pelvoux massif (French Western Alps), with average elevations ranging from 1700 to 2800 m. Spatially-averaged denudation rates, corrected for potential shielding by Little Ice Age glaciers, vary from 0.27 ± 0.05 to 1.07 ± 0.20 mm/yr on millennial timescales. Our results exhibit a correlation ( ρ 2 = 0.56) between denudation rate and mean catchment elevation, in the absence of significant correlation with any other morphometric parameters (relief, slope, catchment size, hypsometry, etc). Although such variations in erosion rates have been previously linked to variations in tectonic uplift rate, the relatively small size and tectonic homogeneity of our study area exclude a strongly variable tectonic control. We interpret the increase in erosion rate with elevation as the effect of frost-controlled processes, which are strongly temperature-dependent. We use a one-dimensional heat-flow model driven by high-resolution instrumental temperature records from the study area to correlate the variability in denudation rates with the integral of the absolute temperature gradient within the frost-cracking window (− 3 to − 8 °C), a proxy of the frost-cracking intensity, for each catchment. The results imply that the efficiency of frost cracking constitutes a major control on catchment-wide denudation rates in the study area, explaining more than half the measured variability in these rates. Our study shows that present-day denudation of the Ecrins–Pelvoux massif is controlled by a climatically driven factor and suggests that frost-cracking processes impose an important control on the post-glacial topographic evolution of mid-latitude mountain belts.

Um modelo alternativo de risco para companhias não-financeiras aplicado ao setor brasileiro de papel e celulose

O Earnings at Risk (EaR) é uma medida de risco financeiro aplicável a empresas não financeiras, assim como o Cash Flow at Risk (CFaR). Esta medida se baseia numa relação que pode ser quantificada através de modelos de regressão linear múltipla, nos quais a variável resposta é a variação do resultado da empresa, e as variáveis explicativas são variações nos diversos fatores de risco. A presença de correlação entre variáveis explicativas (multicolinearidade) neste modelo pode provocar problemas nos cálculos do EaR e do CfaR. Nesse trabalho, apontaremos algumas possíveis consequências deste problema no processo de cálculo do EaR, e apresentaremos uma proposta para contorná-lo baseada na técnica de Análise de Componentes Principais. Escolhemos para análise o setor de agronegócio, especificamente o ramo de papel e celulose. Mostraremos que, na ausência de correlação significativa entre as variáveis, o modelo proposto tem desempenho equivalente ao da regressão linear múltipla usual. Na presença de correlação, encontramos evidências de que o modelo aqui proposto produz previsões mais confiáveis e precisas.

Morphological and molecular diversity within Algerian cowpea (Vigna unguiculata (L.) Walp.) landraces

Twenty landraces of cowpea (Vigna unguiculata (L.) Walp.) scattered throughout Algeria were compared through morphological and genetic characterization. At the morphological level, for qualitative characters there was no intra-landrace variation and for quantitative characters the variations were low except for landrace NAG2 Three different cultigroups were located in Algeria: Biflora that was dominant in the Sahara, Melanophtalmus in the North and Unguiculata including one landrace in Kabylia and two in Sahara. The AMOVA analysis indicated that the genetic variation was lower within than among agro-ecological regions. A Mantel test, revealed a correlation between the qualitative morphological data and the geographical data (R = 0.28; P < 0.01), indicating that the degree of morphological change among landraces was roughly proportional to the geographical distances separating them. Genetic diversity was analyzed by using 11 random amplified polymorphic DNA (RAPD) and 12 inter-simple sequence repeat (ISSR) markers. No intra-landrace variability was found. The eleven RAPD primers yielded 77 bands, of which 45 (58.44%) were polymorphic; the genetic similarity ranged from 66.0 to 96.7%. The twelve ISSR primers provided a total of 104 bands, of which 65 (62.5%) were polymorphic; the genetic similarity ranged from 62.8 to 97.8%. cluster analysis showed a good match between genetic background and geographical distribution, which was confirmed by the results of the Mantel test. In particular, geographical data and genetic data were found to be correlated: (R = 0.33; P < 0.01) for RAPD, (R = 0.37; P < 0.01) for ISSR, and (R = 0.33; P < 0.01) for a combined RAPD-ISSR dataset. Moreover, despite the absence of significant correlation between morphological and RAPD data (R = 0.14; P = 0.14), significant correlations between morphological data and both ISSR (R = 0.27, P < 0.05) and a combined RAPD-ISSR dataset (R = 0.22, P < 0.05) were noted. ISSR markers were better linked to morphological variation than were RAPD markers. However, despite this, genetic distances among these landraces were found to be essentially the same no matter which markers were used.

Heavy metals in mosquito larval habitats in urban Kisumu and Malindi, Kenya, and their impact

Concentrations and distribution of cadmium, chromium, copper, iron, lead, manganese and zinc in mosquito larval habitats in urban Kisumu and Malindi, Kenya and their effect on the presence of Anopheles gambiae, Aedes aegypti, Culex quinquefasciatus and Anopheles funestus larvae were investigated. Manganese and iron were the most prevalent heavy metals in water of larval habitats in urban Kisumu and Malindi, respectively. Iron was the most prevalent heavy metal in bottom sediments in larval habitats in both cities. The highest concentrations of all heavy metals, except cadmium and iron, were recorded in the poorly planned–well drained stratum in the two cities. All heavy metals were more concentrated in human-made than in natural larval habitats. Copper was positively associated with the presence of Ae. aegypti, and lead was associated with the presence of An. gambiae and Ae. aegypti in urban Kisumu. Absence of significant correlation between the other metals and mosquito species in both cities, despite relatively high concentrations, suggest that the local larval populations, including key malaria vectors have adapted to the detected levels of these metals.