192 research outputs found
International Taxation and Multinational Firm Location Decisions
Using a large international firm-level data set, we estimate separate effects of host and parent country taxation on the location decisions of multinational firms. Both types of taxation are estimated to have a negative impact on the location of new foreign subsidiaries. In fact, the impact of parent country taxation is estimated to be relatively large, possibly reflecting its international discriminatory nature. For the cross-section of multinational firms, we find that parent firms tend to be located in countries with a relatively low taxation of foreign-source income. Overall, our results show that parent-country taxation – despite the general possibility of deferral of taxation until income repatriation – is instrumental in shaping the structure of multinational enterprise.corporate taxation, dividend withholding taxation, location decisions
Identification and quantification of pathogenic helminth eggs using a digital image system
AbstractA system was developed to identify and quantify up to seven species of helminth eggs (Ascaris lumbricoides -fertile and unfertile eggs-, Trichuris trichiura, Toxocara canis, Taenia saginata, Hymenolepis nana, Hymenolepis diminuta, and Schistosoma mansoni) in wastewater using different image processing tools and pattern recognition algorithms. The system was developed in three stages. Version one was used to explore the viability of the concept of identifying helminth eggs through an image processing system, while versions 2 and 3 were used to improve its efficiency. The system development was based on the analysis of different properties of helminth eggs in order to discriminate them from other objects in samples processed using the conventional United States Environmental Protection Agency (US EPA) technique to quantify helminth eggs. The system was tested, in its three stages, considering two parameters: specificity (capacity to discriminate between species of helminth eggs and other objects) and sensitivity (capacity to correctly classify and identify the different species of helminth eggs). The final version showed a specificity of 99% while the sensitivity varied between 80 and 90%, depending on the total suspended solids content of the wastewater samples. To achieve such values in samples with total suspended solids (TSS) above 150Â mg/L, it is recommended to dilute the concentrated sediment just before taking the images under the microscope. The system allows the helminth eggs most commonly found in wastewater to be reliably and uniformly detected and quantified. In addition, it provides the total number of eggs as well as the individual number by species, and for Ascaris lumbricoides it differentiates whether or not the egg is fertile. The system only requires basically trained technicians to prepare the samples, as for visual identification there is no need for highly trained personnel. The time required to analyze each image is less than a minute. This system could be used in central analytical laboratories providing a remote analysis service
Scoliosis induced by medullary damage: an experimental study in rabbits
To date, there have been no reports of experiments designed to induce scoliosis
by direct damage of different areas of the spinal cord. In a series of rabbits
with medullary damage, the authors attempted selectively to interrupt the
pathways that mediate proprioceptive input. Unilateral lesion of the dorsal
column and posterior horn of the spinal cord was performed using three different
techniques: coagulation with laser, stereotaxic microcoagulation, and
longitudinal electrocoagulation. Of 32 operated rabbits, 17 developed scoliosis,
exhibiting clear pathologic damage of the spinal cord. Electrophysiologic study,
including EMG and analysis of the tonic -- vibratory reflex, was performed on 10
rabbits with medullary damage (scoliotic and non-scoliotic) and 12 matched
controls. The data suggest disturbance of the sensory afferences that control the
postural tone and consequent muscular imbalance, expressed as reduced activity in
the muscles of the convex side. This work supports the view that loss of
proprioceptive neural impulses caused by medullary damage can induce scoliosi
Transcriptional silencing of the Dickkopfs-3 (Dkk-3) gene by CpG hypermethylation in acute lymphoblastic leukaemia
Dkk-3 is a newly characterised mortalisation-related gene and an antagonist of the Wnt oncogenic signalling pathway whose
expression is decreased in a variety of cancer cell lines, suggesting that the Dkk-3 gene, located at chromosome 11p15.1, functions as
a tumour suppressor gene. Although 11p15 is a ‘hot spot’ for methylation in acute lymphoblastic leukaemia (ALL), the role of Dkk-3
abnormalities has never been evaluated in this disease. We analysed CpG island methylation of the Dkk-3 promoter in six ALL cell
lines and 183 ALL patients. We observed Dkk-3 hypermethylation in all cell lines and in cells from 33% (60/183) of ALL patients.
Moreover, Dkk-3 methylation was associated with decreased Dkk-3 mRNA expression and this expression was restored after
exposure to the demethylating agent 5-AzaC. Clinical features did not differ between hypermethylated and unmethylated patients.
Estimated disease-free survival (DFS) and overall survival at 10 and 11 years, respectively, were 49.8 and 45.6% for normal patients
and 10.5 and 15.1% for hypermethylated patients (P¼0.001 and 0.09). Multivariate analysis demonstrated that Dkk-3 methylation
was an independent prognostic factor predicting DFS (P¼0.0009). Our data suggest that Dkk-3 methylation occurs at an early stage
in ALL pathogenesis and probably influences the clinical behaviour of the disease
Langerhans cell histiocytosis in the maxillofacial area in adults : report of three cases
Langerhans cell histiocytosis (LCH) is a disease of unknown etiology, characterized by proliferation of pathological Langerhans cells within different organs. It mainly affects children, but adult cases also occur, with an incidence rate of one to two per million. The head and neck are affected in almost 90% of cases. Diagnosis is made by means of histopathological analysis, and imaging studies are necessary in order to determine extent of the disease. There are no controlled trials proposing an optimal treatment protocol for LCH. Prognosis in adults is generally good due to the slow evolution of the disease and its favourable response to treatment. In our report, we present three cases of LCH in patients aged 16, 24, and 28 years respectively, with primary manifestation in the maxillofacial area. A literature review was also conducted
Promoter hypermethylation of cancer-related genes: a strong independent prognostic factor in acute lymphoblastic leukemia
Promoter hypermethylation plays an important
role in the inactivation of cancerrelated
genes. This abnormality occurs
early in leukemogenesis and seems to be
associated with poor prognosis in acute
lymphoblastic leukemia (ALL). To determine
the extent of hypermethylation in
ALL, we analyzed the methylation status
of the CDH1, p73, p16, p15, p57, NES-1,
DKK-3, CDH13, p14, TMS-1, APAF-1,
DAPK, PARKIN, LATS-1, and PTEN genes
in 251 consecutive ALL patients.Atotal of
77.3% of samples had at least 1 gene
methylated, whereas 35.9% of cases had
4 or more genes methylated. Clinical features
and complete remission rate did not
differ among patients without methylated
genes, patients with 1 to 3 methylated
genes (methylated group A), or patients
with more than 3 methylated genes (methylated
group B). Estimated disease-free
survival (DFS) and overall survival (OS) at
11 years were 75.5% and 66.1%, respectively,
for the nonmethylated group; 37.2%
and 45.5% for methylated group A; and
9.4% and 7.8% for methylated group B
(P < .0001 and P .0004, respectively).
Multivariate analysis demonstrated that
the methylation profile was an independent
prognostic factor in predicting DFS
(P < .0001) and OS (P .003). Our results
suggest that the methylation profile may
be a potential new biomarker of risk prediction
in AL
Promoter hypomethylation of the LINE-1 retrotransposable elements activates sense/antisense transcription and marks the progression of chronic myeloid leukemia
Aberrant genome-wide hypomethylation is thought to be
related to tumorigenesis by promoting genomic instability.
Since DNA methylation is considered an important mechanism
for the silencingof retroelements, hypomethylation
in human tumors may lead to their reactivation. However,
the role of DNA hypomethylation in chronic myeloid
leukemia (CML) remains to be elucidated. In this study,
the methylation status of the LINE-1 (L1) retrotransposon
promoter was analysed in CML samples from the chronicphase
(CP, n¼140) and the blast crisis (BC, n¼47). L1
hypomethylation was significantly more frequent in BC
(74.5%) than in CP (38%) (Po0.0001). Furthermore,
L1 hypomethylation led to activation of both ORF1 sense
transcription (Po0.0001) and c-MET gene antisense
transcription (Po0.0001), and was significantly associated
with high levels of BCR–ABL (P¼0.02) and
DNMT3b4 (P¼0.001) transcripts. Interestingly, in
CP-CML, extensive L1 hypomethylation was associated
with poorer prognosis in terms of cytogenetic response
to interferon (P¼0.004) or imatinib (P¼0.034) and
progression-free survival (P¼0.005). The above results
strongly suggest that activation of both sense and
antisense transcriptions by aberrant promoter hypomethylation
of the L1 elements plays a role in the progression
and clinical behavior of the CML
DISEÑO DEL PULSO ÓPTIMO DE RIEGO EN EL CULTIVO DE FRESA CON EL MODELO NUMÉRICO HYDRUS 2D
[ES] El cultivo intensivo de fresa, que se desarrolla en macrotúneles de plástico sobre
lomos acolchados, demanda volúmenes importantes de agua para satisfacer las
necesidades hÃdricas del cultivo asà como para labores de preparación del suelo o alomado
y riego de apoyo en la fase de plantación. El riego de la fresa es especialmente complejo
dado que es un cultivo que se produce bajo plástico en suelos muy arenosos (habitualmente
con un contenido de arena superior al 90%), con escasa capacidad de retención de agua. A
pesar de esta dificultad, no es habitual que exista una programación del riego basada en la
medida de las principales variables que afectan al cálculo de las necesidades hÃdricas del
cultivo. En este trabajo se proponen medidas de mejora en el manejo del riego, basadas en
la determinación del pulso óptimo que evite las pérdidas por percolación en tres fases de
desarrollo del cultivo. Para ello se ha utilizado el modelo de simulación del movimiento del
agua en el suelo Hydrus 2D. Se han simulado diferentes estrategias de riego para aplicar la
ETc del cultivo con emisores de 5 l.h-1.m en tres etapas diferentes del cultivo, inicio,
mediados, y final de campaña y en las que por término medio se necesitan tiempos de riego
que oscilan entre los 10-20 minutos al inicio de la campaña y 40-60 minutos al final de
campañaGarcÃa Morillo, J.; RodrÃguez-DÃaz, J.; MartÃn Arroyo, M.; Camacho Poyato, E.; Montesinos Barrios, P. (2015). DISEÑO DEL PULSO ÓPTIMO DE RIEGO EN EL CULTIVO DE FRESA CON EL MODELO NUMÉRICO HYDRUS 2D. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1472OC
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