Approximately 57% of the Brazilian northeast region is recognized as semi-arid land and has been undergoing intense land use processes in the last decades, which have resulted in severe degradation ...of its natural assets. Therefore, the objective of this study is to identify the areas that are susceptible to desertification in this region based on the 11 influencing factors of desertification (pedology, geology, geomorphology, topography data, land use and land cover change, aridity index, livestock density, rural population density, fire hot spot density, human development index, conservation units) which were simulated for two different periods: 2000 and 2010. Each indicator were assigned weights ranging from 1 to 2 (representing the best and the worst conditions), representing classes indicating low, moderate and high susceptibility to desertification. The results indicate that 94% of the Brazilian northeast region is under moderate to high susceptibility to desertification. The areas that were susceptible to soil desertification increased by approximately 4.6% (83.4 km2) from 2000 to 2010. The implementation of the methodology provides the technical basis for decision-making that involves mitigating actions and the first comprehensive national assessment within the United Nations Convention to Combat Desertification framework.
In tropical forest areas with highly weathered soils, organic matter plays an important role in soil functioning and forest sustainability. When forests are clear-cut, the soil begins almost ...immediately to lose organic matter, triggering a series of soil degradation processes, the extent and intensity of which depends on soil management. Depending on the level of soil degradation, the rate at which the system can re-establish itself can be slow and may require the use of degraded land restoration techniques. This study aimed at evaluating the potential of pioneer leguminous nitrogen-fixing trees to recuperate degraded land. The area studied – located in the coastal town of Angra dos Reis in the State of Rio de Janeiro, Brazil – was planted with seven species of fast-growing leguminous nitrogen-fixing trees in 1991. The nutrient concentrations (Ca, Mg, P and K) and N and C stocks in the soil and litter were determined, in addition to the free- and occluded-light fractions of soil organic matter. Soil samples were also collected from two reference areas: (1) an area of undisturbed native forest; and (2) a deforested area spontaneously colonised by Guinea grass (
Panicum maximum). The nutrient stocks in the litter of the restored area were similar to those found in native forest. The recuperation technique used was able to re-establish the soil C and N stocks after 13 years. C and N increased by 1.73 and 0.13
Mg
ha
−1
year
−1, respectively. The free-light fraction was highest in the recuperated area and lowest in the deforested area. The occluded-light fraction of the recuperated area was higher than that of the native forest only in the 0–5
cm layer. Both the free-light and occluded fractions were higher in the native forest and recuperated areas than in the deforested area. Since the free-light and the occluded-light fractions are the result of litterfall and decomposition, these results – combined with the data of litter stocks and soil C and N stocks – indicate that the use of legume trees was efficient in re-establishing the nutrient cycling processes of the systems. These results also show that recovering degraded land with this technique is effective in sequestering carbon dioxide from the atmosphere at high rates.
We survey 1,050 Chief Financial Officers (CFOs) in the U.S., Europe, and Asia to directly assess whether their firms are credit constrained during the global financial crisis of 2008. We study ...whether corporate spending plans differ conditional on this survey-based measure of financial constraint. Our evidence indicates that constrained firms planned deeper cuts in tech spending, employment, and capital spending. Constrained firms also burned through more cash, drew more heavily on lines of credit for fear banks would restrict access in the future, and sold more assets to fund their operations. We also find that the inability to borrow externally caused many firms to bypass attractive investment opportunities, with 86% of constrained U.S. CFOs saying their investment in attractive projects was restricted during the credit crisis of 2008. More than half of the respondents said they canceled or postponed their planned investments. Our results also hold in Europe and Asia, and in many cases are stronger in those economies. Our analysis adds to the portfolio of approaches and knowledge about the impact of credit constraints on real firm behavior.
The lot-sizing and cutting-stock problems arise, in general, in manufacturing industries as subsequent processes. Many authors have addressed these problems separately; however, some studies have ...considered integrated approaches to these problems in recent practical applications. This paper aims to introduce a new model for integrated lot-sizing, one-dimensional cutting-stock and two-dimensional cutting-stock problems. This integrated model can be used to address the papermaking process as a three-phase subsequent process, which starts from the production of jumbos and ends with the paper sheets used in daily life. The first phase of the process is modeled according to a lot-sizing problem, where the quantities of jumbos are determined to meet the demand of the entire planning horizon. The second phase is modeled as a one-dimensional cutting-stock problem, where the jumbos are cut into smaller reels. The reels are used as raw material for the third phase of the process, where they are cut again into sheets employing a two-dimensional cutting-stock problem. A heuristic algorithm that uses the column generation and relax-and-fix techniques is applied to evaluate the proposed model from a series of experiments. Gains of up 16.5% were observed compared to the solution obtained with no integration among the production phases. Additional analyses of the model behavior under multiple scenarios resulted in significant findings, as the increasing costs’ reduction as more product types are considered and the use of more efficient cutting patterns resulting in reduced material waste.
One of the challenges for clustering resides in dealing with data distributed in separated repositories, because most clustering techniques require the data to be centralized. One of them, k-means, ...has been elected as one of the most influential data mining algorithms for being simple, scalable and easily modifiable to a variety of contexts and application domains. Although distributed versions of k-means have been proposed, the algorithm is still sensitive to the selection of the initial cluster prototypes and requires the number of clusters to be specified in advance. In this paper, we propose the use of evolutionary algorithms to overcome the k-means limitations and, at the same time, to deal with distributed data. Two different distribution approaches are adopted: the first obtains a final model identical to the centralized version of the clustering algorithm; the second generates and selects clusters for each distributed data subset and combines them afterwards. The algorithms are compared experimentally from two perspectives: the theoretical one, through asymptotic complexity analyses; and the experimental one, through a comparative evaluation of results obtained from a collection of experiments and statistical tests. The obtained results indicate which variant is more adequate for each application scenario.
Background and purpose
The objective of our study was to evaluate sex differences in the impact of weight and abdominal obesity on the risk of ischemic stroke.
Methods
We included 388 patients with ...ischemic stroke (aged <75 years) assessed consecutively in our hospital and 732 controls matched by age and sex. Vascular risk factors and anthropometric data (waist circumference, weight and height) were recorded. The impact of three anthropometric variables body mass index (BMI), waist circumference and waist to height ratio on ischemic stroke risk was calculated. These variables were divided into quartiles for a comprehensive comparison between cases and controls, stratified by sex and adjusted in logistic regression by age and vascular risk factors. Further logistic regression using dummy variables was performed to evaluate the association between BMI‐adjusted abdominal obesity and stroke risk.
Results
Increased BMI was not associated with increased stroke risk overall or in women, but was a protective factor in men P = 0.03; odds ratio (OR), 0.59 (0.37–0.94). Abdominal obesity was a risk factor for stroke in women, in both waist circumference P < 0.001; OR, 5.79 (3.10–10.85) and waist to height ratio P < 0.001; OR, 3.61 (1.99–6.54) analyses, but was not significant in men. When considered independently of BMI, abdominal obesity was a risk factor in both sexes, but the strength of the association was significantly higher in women.
Conclusions
Increased BMI was related to a lower risk of stroke in men. Abdominal obesity was associated with ischemic stroke in women. The impact of abdominal obesity on stroke risk differs by sex.
Background and purpose
Patients with acute intracerebral hemorrhage (ICH) pretreated with antithrombotic drugs may have increased early hematoma growth, which would increase mortality risk. The ...effect of antiplatelet (AP) and vitamin K antagonist (VKA) pretreatment on ultra‐early hematoma growth (uHG) and its relationship with mortality in patients with acute supratentorial ICH was analyzed.
Methods
This is an observational retrospective study of a prospective register of 197 ICH patients with first computed tomography (CT) scan taken <6 h from ICH symptom onset. ICH volume was calculated by the ABC/2 formula and uHG by the baseline ICH volume/onset‐to‐CT time (ml/h) formula. The uHG analysis took into account the patient's pretreatment (none, AP or VKA) and the relationship between uHG and very‐early (first 24 h) and 3‐month mortality.
Results
In the pretreatment group, 50 (25.4%) patients were treated with AP and 37 (18.8%) with VKA. The median (interquartile range 25–75) uHG was 19.7 ml/h (2.9–44.8) for AP pretreated patients, 16.2 ml/h (5.1–42.5) for VKA pretreated patients and 8.4 ml/h (2.4–21.8) for non‐pretreated patients, P = 0.019. The uHG was higher in patients with very‐early 42.1 ml/h (20.1–79.6) and total 3‐month mortality 28.0 ml/h (15.8–52.5) compared with survivors 3.9 ml/h (1.5–10.4), P < 0.0001. Adjusted by ICH severity and previous functional status, uHG was an independent factor related to very‐early (P = 0.028) and total 3‐month mortality (P = 0.014).
Conclusions
Patients pretreated with antithrombotics have much higher uHG, which would explain the increased mortality in these patients compared to untreated patients.
The structural determinants of the interaction of the G‐quadruplex (G4) motif found in precursor miRNA 149 (rG4) with the acridine orange derivative C8, a G4 ligand stabilizer possessing anticancer ...activity, and the protein nucleolin (overexpressed in cancer cells) were investigated by Nuclear Magnetic Resonance (NMR) spectroscopy. For the rG4/C8 complex, the results revealed a strong stabilizing interaction between the aromatic core and the iodinated ring of the C8 ligand with the rG4 structure. The NMR study revealed also different interaction patterns between nucleolin and rG4 and nucleolin and rG4/C8 complex. In the absence of the ligand, rG4 establishes interactions with polar residues of the protein while for the rG4/C8 complex, these contacts are mainly established with amino acids that have hydrophobic side chains. However, nucleolin chemical shift perturbation studies in the presence of rG4 or rG4/C8 reveal the same location between domains 1 and 2 of the protein, which suggests that the rG4 and rG4/C8 complex bind in this region. This puzzling structural study opens a new framework to study rG4/ligand/nucleolin complexes that might impact the biogenesis of miRNA 149.
Structural study of the complex between nucleolin, a protein involved in a myriad of human diseases, and the RNA G4 found in pre‐miRNA 149 stabilized by the compound C8, known for its G4 stabilizing properties, was conducted. The results provide important molecular determinants at the atomic level and may pave the way for future investigations in the field.
Display omitted
The development of novel biomarkers for early-stage diagnosis of prostate cancer (PCa) has attracted the attention of researchers in the last decade. Nucleolin (NCL) has emerged as a ...possible biomarker of PCa due to its high expression levels in the surface of PCa cells and affinity towards parallel G4s since it contains four RNA-binding domains (RBDs). Herein, we developed a novel strategy based on a microfluidic platform for the detection of NCL in biological samples, such as human plasma. The RNA G4 (rG4) sequence found in human precursor microRNA 92b (pre-miR-92b) was used as a molecular recognition probe since it forms a single dominant parallel rG4 conformation in the presence of 0.1 mM K+ as confirmed by NMR spectroscopy. The additional stability of the rG4 structure was provided by the acridine orange derivative ligand C8, which stabilizes the pre-miR-92b rG4 structure, as denoted by an increase in more than 30 °C of its melting temperature. FRET-melting assay revealed a remarkable synergistic effect of NCL RBD1,2 and C8 on the stabilization of the pre-miR-92b rG4. The binding of pre-miR-92b to NCL RBD1,2 was determined by in silico studies, which revealed a binding pocket formed by a 12-residue linker between RBD1 and RBD2. Both, pre-miR-92b rG4 and pre-miR-92b rG4/C8 complex demonstrated high affinity towards NCL RBD1,2, as proved by fluorimetric titrations (KD range between 10-12 and 10-9 M). The stability and nuclease resistance of pre-miR-92b rG4 and pre-miR-92b rG4/C8 complex were evaluated as molecular recognition probes to capture and detect NCL. Finally, the microfluidic platform detects NCL in complex biological samples, such as human plasma. Overall, this work demonstrates the usefulness of the microfluidic platform based on the pre-miR-92b to detect NCL and the possibility to be used as a valuable biomedical tool in PCa diagnosis.
The objective was to evaluate the effects of growth hormone (GH) on the survival, growth, maturation, and fertilization of oocytes derived from caprine preantral ovarian follicles cultured
in vitro. ...Preantral follicles were isolated from the cortex of caprine ovaries and individually cultured for 18 d in the absence (control) or presence of bovine GH at concentrations of 10 or 50 ng/mL (GH10 and GH50, respectively). Follicle development was evaluated on the basis of survival, antral cavity formation, diameter increase, and the presence of healthy cumulus-oocyte complexes and mature oocytes. After culture, oocytes were subjected to
in vitro maturation (IVM) and
in vitro fertilization (IVF). The rate of antrum formation after Day 6 of culture was higher in both GH10 and GH50 than in the control (81.0, 92.7, and 47.6%, respectively, P < 0.05). Percentages of grown oocytes that were acceptable for IVM were also higher (P < 0.05) in GH-treated groups than in the control (54.8, 48.8, and 11.9% for GH10, GH50, and Control). A higher percentage of oocytes in the GH50 treatment underwent meiotic resumption (50.0%), produced mature oocytes, and enabled production of an embryo after IVF than in the control group (0.0%; P < 0.05). In conclusion, GH promoted
in vitro growth and maturation of goat preantral follicle oocytes and enabled production of an embryo. Furthermore, this study was apparently the first to produce a caprine embryo by
in vitro fertilization of oocytes derived from preantral follicles grown
in vitro.
PDF
