Wim Hacking - Academia.edu (original) (raw)
Papers by Wim Hacking
Journal of Vascular Research, 1996
Micro-editing is a very time-consuming process. As analysts often want to avoid wrong records to ... more Micro-editing is a very time-consuming process. As analysts often want to avoid wrong records to pass the edits, the boundaries for micro-checks are often set conservatively, i.e. only error-less records are accepted. This means that there are often many checks with narrow tolerances resulting in too many mistakes that need to be resolved manually by analysts. An example of a frequently used edit is that the relative change compared to the last period cannot exceed ± 10%. Generally, this approach results in a considerable amount of over-editing. Another problem with editing at the micro data level is that the analysts cannot assess the relative importance of errors. Each marked item has the same weight and needs the same amount of time for correction. However, many errors have a neglible impact on the final estimates: either they are small or they cancel out.
1. Statistics Netherlands has developed a software package called MacroView that enables an effic... more 1. Statistics Netherlands has developed a software package called MacroView that enables an efficient development of custom-tailored macro-editing tools. Generic functionalities of macro-editing tools are implemented in MacroView. These functionalities are in fact the building blocks of all macroediting tools developed in MacroView. To actually build such a custom-tailored macro-editing tool using these building blocks, a script language can be used. Scripts specify which building blocks are combined in a macro-editing tool and how. Macro-editing tools developed in MacroView are currently being used in the redesigned Dutch Structural Business Statistics and Road Statistics. At the moment MacroView scripts are developed and tested for the redesigned Short term Statistics.
Journal of Vascular Research, 1996
There are basically two types of branching patterns in the terminal part of the arteriolar tree. ... more There are basically two types of branching patterns in the terminal part of the arteriolar tree. On the one hand, in a number of tissues, including the developing chick embryo chorioallantoic membrane (CAM), the pattern is dichotomous, whereas in other tissues many arteriolar-arteriolar connections, arcades, are found. The structure of the branching pattern depends on the local physical and chemical environment. The goal of this study was to investigate whether substances with an effect on vascular growth influence the vascular branching pattern. We treated chick embryo CAMs daily from day 7 to day 14 postfertilization with 0.9% NaCl, angiotensin II (ANG-II), ANG-II in combination with different angiotensin receptor subtype antagonists, i.e., losartan and CGP 42112A, or the prostaglandin synthesis inhibitor acetylsalicylic acid (ASA). Arcade formation was quantified by counting the number of arcades per cm2 treated area, the branch-node ratio and mean surface area of arcade loops. ANG-II caused a 2-fold increase in the number of arcades versus 0.9% NaCl. Addition of ASA or losartan caused a further enhancement of arcade formation expressed in the number and branch-node ratio. CGP 42112A had no significant effect on arcade formation. From these data we hypothesize that ANG-II stimulates the process of capillary upgrading to arterioles by stimulation of arteriolar smooth muscle cell growth. Prostaglandins normally counteract this effect. After blockade of prostaglandin action, the ANG-II-induced arterialization is enhanced, resulting in pronounced arcade formation. The actions of losartan may be related to its inhibitory effects on prostaglandins rather than angiotensin receptor antagonism.
Branching in Nature, 2001
The formation of new blood vessels is an important process in embryonic development and in (patho... more The formation of new blood vessels is an important process in embryonic development and in (patho) physiological conditions like cyclic vessel growth in the endometrium, wound healing, diabetic retinopathy, and tumor growth. Lack of blood vessel growth is a key event in pathologies like essential hypertension, peptic ulcers, and bowel atresia. At present clinical trials are undertaken with anti-angiogenic drugs to interfere with tumor development [2, 3, 7, 14, 19]. Pro-angiogenic therapies, or “therapeutic angiogenesis” are employed in the treatment of ischemia related events such as coronary artery disease (“infarction”) and peripheral artery occlusive diseases [11, 20, 56, 59, 67]. This therapy aims at stimulation of collateral artery formation to the ischemic region thereby restoring flow and oxygen delivery.
In this report we will describe a model that is developed to evaluate the quality of structural b... more In this report we will describe a model that is developed to evaluate the quality of structural business statistics of the EU Member States in relation to the survey costs. Starting point is the survey process that determines the quality and costs of the statistics produced. By means of an activity-quality matrix and activity-costs matrices we link quality aspects, production costs and response burden to the activities in the survey process. In order to assess the quality of the survey results we derive two quantitative measures, one for the sampling error and one for the non sampling error due to non response. We also give a number of qualitative measures with respect to the non sampling errors. We define cost functions for each activity of the survey process taking into account that information on costs is difficult to obtain. The optimal survey strategy is calculated by minimizing the variance subject to the budget restriction. In evaluating the trade off between precision and costs, the quality and cost indicators are defined as a function of a limited set of instruments which can be used to simulate changes in the process characteristics. The model and the simulations are implemented in a computer program. A questionnaire was designed to collect the information needed from the Member States.
Journal of Hypertension, 1998
The formation of new blood vessels is an important process in embryonic development and in physio... more The formation of new blood vessels is an important process in embryonic development and in physiological repair processes. Abnormalities in blood vessel growth have been associated with various pathologies. The basic observation underlying the hypothesis that essential hypertension is based on an impaired capacity for vascular growth is the nature of the structural alterations of microvascular beds in essential hypertension. Recent advances in understanding the molecular and cellular mechanisms of vascular growth suggest that the remodeling of individual vessels and vascular networks in hypertension may be a pathological variant of the formation of mature networks. Genetic and fetal influences appear to have significant effects in determining impaired vascular development as an early cause of essential hypertension.
Journal of Vascular Research, 1996
Micro-editing is a very time-consuming process. As analysts often want to avoid wrong records to ... more Micro-editing is a very time-consuming process. As analysts often want to avoid wrong records to pass the edits, the boundaries for micro-checks are often set conservatively, i.e. only error-less records are accepted. This means that there are often many checks with narrow tolerances resulting in too many mistakes that need to be resolved manually by analysts. An example of a frequently used edit is that the relative change compared to the last period cannot exceed ± 10%. Generally, this approach results in a considerable amount of over-editing. Another problem with editing at the micro data level is that the analysts cannot assess the relative importance of errors. Each marked item has the same weight and needs the same amount of time for correction. However, many errors have a neglible impact on the final estimates: either they are small or they cancel out.
1. Statistics Netherlands has developed a software package called MacroView that enables an effic... more 1. Statistics Netherlands has developed a software package called MacroView that enables an efficient development of custom-tailored macro-editing tools. Generic functionalities of macro-editing tools are implemented in MacroView. These functionalities are in fact the building blocks of all macroediting tools developed in MacroView. To actually build such a custom-tailored macro-editing tool using these building blocks, a script language can be used. Scripts specify which building blocks are combined in a macro-editing tool and how. Macro-editing tools developed in MacroView are currently being used in the redesigned Dutch Structural Business Statistics and Road Statistics. At the moment MacroView scripts are developed and tested for the redesigned Short term Statistics.
Journal of Vascular Research, 1996
There are basically two types of branching patterns in the terminal part of the arteriolar tree. ... more There are basically two types of branching patterns in the terminal part of the arteriolar tree. On the one hand, in a number of tissues, including the developing chick embryo chorioallantoic membrane (CAM), the pattern is dichotomous, whereas in other tissues many arteriolar-arteriolar connections, arcades, are found. The structure of the branching pattern depends on the local physical and chemical environment. The goal of this study was to investigate whether substances with an effect on vascular growth influence the vascular branching pattern. We treated chick embryo CAMs daily from day 7 to day 14 postfertilization with 0.9% NaCl, angiotensin II (ANG-II), ANG-II in combination with different angiotensin receptor subtype antagonists, i.e., losartan and CGP 42112A, or the prostaglandin synthesis inhibitor acetylsalicylic acid (ASA). Arcade formation was quantified by counting the number of arcades per cm2 treated area, the branch-node ratio and mean surface area of arcade loops. ANG-II caused a 2-fold increase in the number of arcades versus 0.9% NaCl. Addition of ASA or losartan caused a further enhancement of arcade formation expressed in the number and branch-node ratio. CGP 42112A had no significant effect on arcade formation. From these data we hypothesize that ANG-II stimulates the process of capillary upgrading to arterioles by stimulation of arteriolar smooth muscle cell growth. Prostaglandins normally counteract this effect. After blockade of prostaglandin action, the ANG-II-induced arterialization is enhanced, resulting in pronounced arcade formation. The actions of losartan may be related to its inhibitory effects on prostaglandins rather than angiotensin receptor antagonism.
Branching in Nature, 2001
The formation of new blood vessels is an important process in embryonic development and in (patho... more The formation of new blood vessels is an important process in embryonic development and in (patho) physiological conditions like cyclic vessel growth in the endometrium, wound healing, diabetic retinopathy, and tumor growth. Lack of blood vessel growth is a key event in pathologies like essential hypertension, peptic ulcers, and bowel atresia. At present clinical trials are undertaken with anti-angiogenic drugs to interfere with tumor development [2, 3, 7, 14, 19]. Pro-angiogenic therapies, or “therapeutic angiogenesis” are employed in the treatment of ischemia related events such as coronary artery disease (“infarction”) and peripheral artery occlusive diseases [11, 20, 56, 59, 67]. This therapy aims at stimulation of collateral artery formation to the ischemic region thereby restoring flow and oxygen delivery.
In this report we will describe a model that is developed to evaluate the quality of structural b... more In this report we will describe a model that is developed to evaluate the quality of structural business statistics of the EU Member States in relation to the survey costs. Starting point is the survey process that determines the quality and costs of the statistics produced. By means of an activity-quality matrix and activity-costs matrices we link quality aspects, production costs and response burden to the activities in the survey process. In order to assess the quality of the survey results we derive two quantitative measures, one for the sampling error and one for the non sampling error due to non response. We also give a number of qualitative measures with respect to the non sampling errors. We define cost functions for each activity of the survey process taking into account that information on costs is difficult to obtain. The optimal survey strategy is calculated by minimizing the variance subject to the budget restriction. In evaluating the trade off between precision and costs, the quality and cost indicators are defined as a function of a limited set of instruments which can be used to simulate changes in the process characteristics. The model and the simulations are implemented in a computer program. A questionnaire was designed to collect the information needed from the Member States.
Journal of Hypertension, 1998
The formation of new blood vessels is an important process in embryonic development and in physio... more The formation of new blood vessels is an important process in embryonic development and in physiological repair processes. Abnormalities in blood vessel growth have been associated with various pathologies. The basic observation underlying the hypothesis that essential hypertension is based on an impaired capacity for vascular growth is the nature of the structural alterations of microvascular beds in essential hypertension. Recent advances in understanding the molecular and cellular mechanisms of vascular growth suggest that the remodeling of individual vessels and vascular networks in hypertension may be a pathological variant of the formation of mature networks. Genetic and fetal influences appear to have significant effects in determining impaired vascular development as an early cause of essential hypertension.