Opportunities and constraints for improved vegetable production technology in tropical Asia

A description of the characteristics of vegetable production in tropical Asia is presented. The description is followed by a discussion of the opportunities and constraints of improved non-seed vegetable production technologies. Sowing of seeds and seedling emergence, transplant production, irrigation, mulching, fertiliser use, crop protection and weed control methods, protected cultivation and harvest date planning are discussed in relation to their use and impact. Conditions for successful introduction of new technologies and the role of outside actors are discussed. It is argued that in order to increase the success of adoption of improved technologies, farmers and public and private institutions should work together. With increasing prosperity, the demand for vegetables, especially in the expanding urban areas, will increase, leading to the intensification of production and higher profitability. With better profitability, the application of mulch, drip irrigation, fertigation and protected cultivation will become more common. With increasing production, harvest date planning as related to year-round city market demand, will become essential to improve profitability. It is recommended that, next to the development and introduction of improved production technologies, research and extension on vegetables in tropical Asia, should also focus on methods to improve harvest date planning and year-round suppl

Gewassaldo van Kouseband en Sopropo in drie Surinaamse tuinbouwgebieden : verslag van een survey in Commewijne, Saramacca en Wanica

In september 2010 is een survey uitgevoerd in de tuinbouwgebieden Commewijne, Saramacca en Wanica. In Saramacca en Wanica werden elk 5 telers van sopropo en kouseband geïnterviewd en in Commewijne werden 5 kouseband en 5 sopropo telers geïnterviewd. De telers werden met behulp van een vragenformulier bevraagd naar de kosten en opbrengsten van een kouseband of sopropo teelt. Ook werd gevraagd naar de benodigde arbeid voor de diverse teelthandelingen. Uit dit onderzoek kwam naar voren dat over het algemeen er weinig teeltregistratie door de telers zelf wordt gedaan. De meeste gegevens zijn afkomstig op basis van herinnering. Voor het opstellen van de gewassaldo’s moesten aannames gemaakt worden op het gebied van teeltduur, oogstperiode en gewasbeschermingsmiddel gebruik. Op basis van de opgestelde gewassaldo’s blijken tussen de drie onderzochte regio’s verschillen aanwezig te zijn in bemestingsstrategieën, opbrengsten en benodigde arbeid

Pertumbuhan dan Hasil Tanaman Paprika yang Ditanam pada Dua Tipe Konstruksi Rumah Plastik dan Dua Jenis Media Tanam

. Percobaan untuk mengetahui pertumbuhan dan hasil tanaman paprika yang ditanam pada 2 tipe konstruksi rumah plastik dan 2 jenis media tanam, dilaksanakan di Kebun Percobaan Balai Penelitian Tanaman Sayuran, Lembang (1.250 m dpl.), Jawa Barat dari bulan Mei 2004 sampai Februari 2005. Tanaman paprika ditanam pada 2 tipe konstruksi rumah plastik, yaitu (1) rumah plastik bambu dan (2) rumah plastik tipe kayu-metal. Jarak tanam yang digunakan pada masing-masing rumah plastik adalah 1,20x0,50 m. Dua jenis media tanam yaitu perlite dan arang sekam juga diteliti sebagai faktor perlakuan. Rancangan percobaan yang digunakan adalah acak kelompok dan masing-masing kombinasi perlakuan diulang 6 kali. Hasil penelitian menunjukkan bahwa tipe konstruksi rumah plastik berpengaruh terhadap intensitas cahaya matahari yang dapat diintersepsi di rumah plastik dan rumah plastik tipe kayu-metal dapat mengintersepsi cahaya matahari 12,6% lebih tinggi daripada rumah plastik bambu. Bobot dan jumlah buah per tanaman dari tanaman paprika yang ditanam di rumah plastik tipe kayu-metal lebih tinggi daripada tanaman paprika yang ditanam di rumah plastik bambu. Tanaman paprika yang ditanam di media tanam arang sekam memberikan bobot dan jumlah buah per tanaman paprika lebih tinggi daripada media tanam perlite. Untuk mengatasi temperatur terlalu tinggi di rumah plastik tipe kayu-metal dapat dilakukan dengan membuat ventilasi di atap dan dengan cara menambah populasi tanaman

The impact of loco-regional recurrences on metastatic progression in early-stage breast cancer: a multistate model

To study whether the effects of prognostic factors associated with the occurrence of distant metastases (DM) at primary diagnosis change after the incidence of loco-regional recurrences (LRR) among women treated for invasive stage I or II breast cancer. The study population consisted of 3,601 women, enrolled in EORTC trials 10801, 10854, or 10902 treated for early-stage breast cancer. Data were analysed in a multivariate, multistate model by using multivariate Cox regression models, including a state-dependent covariate. The presence of a LRR in itself is a significant prognostic risk factor (HR: 3.64; 95%-CI: 2.02-6.5) for the occurrence of DM. Main prognostic risk factors for a DM are young age at diagnosis (</=40: HR: 1.79; 95%-CI: 1.28-2.51), larger tumour size (HR: 1.58; 95%-CI: 1.35-1.84) and node positivity (HR: 2.00; 95%-CI: 1.74-2.30). Adjuvant chemotherapy is protective for a DM (HR: 0.66; 95%-CI: 0.55-0.80). After the occurrence of a LRR the latter protective effect has disappeared (P = 0.009). The presence of LRR in itself is a significant risk factor for DM. For patients who are at risk of developing LRR, effective local control should be the main target of therapy

An Edgeworth expansion for finite population L-statistics

In this paper, we consider the one-term Edgeworth expansion for finite population L-statistics. We provide an explicit formula for the Edgeworth correction term and give sufficient conditions for the validity of the expansion which are expressed in terms of the weight function that defines the statistics and moment conditions.Comment: 14 pages. Minor revisions. Some explanatory comments and a numerical example were added. Lith. Math. J. (to appear

A direct probe of cosmological power spectra of the peculiar velocity field and the gravitational lensing magnification from photometric redshift surveys

The cosmological peculiar velocity field (deviations from the pure Hubble flow) of matter carries significant information on dark energy, dark matter and the underlying theory of gravity on large scales. Peculiar motions of galaxies introduce systematic deviations between the observed galaxy redshifts z and the corresponding cosmological redshifts z_cos. A novel method for estimating the angular power spectrum of the peculiar velocity field based on observations of galaxy redshifts and apparent magnitudes m (or equivalently fluxes) is presented. This method exploits the fact that a mean relation between z_cos and m of galaxies can be derived from all galaxies in a redshift-magnitude survey. Given a galaxy magnitude, it is shown that the z_cos(m) relation yields its cosmological redshift with a 1-sigma error of sigma_z~0.3 for a survey like Euclid (~10^9 galaxies at z<~2), and can be used to constrain the angular power spectrum of z-z_cos(m) with a high signal-to-noise ratio. At large angular separations corresponding to l<~15, we obtain significant constraints on the power spectrum of the peculiar velocity field. At 15<~l<~60, magnitude shifts in the z_cos(m) relation caused by gravitational lensing magnification dominate, allowing us to probe the line-of-sight integral of the gravitational potential. Effects related to the environmental dependence in the luminosity function can easily be computed and their contamination removed from the estimated power spectra. The amplitude of the combined velocity and lensing power spectra at z~1 can be measured with <~5% accuracy.Comment: 22 pages, 3 figures; added a discussion of systematic errors, accepted for publication in JCA

Parametric hazard rate models for long-term sickness absence

PURPOSE: In research on the time to onset of sickness absence and the duration of sickness absence episodes, Cox proportional hazard models are in common use. However, parametric models are to be preferred when time in itself is considered as independent variable. This study compares parametric hazard rate models for the onset of long-term sickness absence and return to work. METHOD: Prospective cohort study on sickness absence with four follow-up years of 53,830 employees working in the private sector in the Netherlands. The time to onset of long-term (>6 weeks) sickness absence and return to work were modelled by parametric hazard rate models. RESULTS: The exponential parametric model with a constant hazard rate most accurately described the time to onset of long-term sickness absence. Gompertz-Makeham models with monotonically declining hazard rates best described return to work. CONCLUSIONS: Parametric models offer more possibilities than commonly used models for time-dependent processes as sickness absence and return to work. However, the advantages of parametric models above Cox models apply mainly for return to work and less for onset of long-term sickness absence

Modified Chaplygin Gas and Solvable F-essence Cosmologies

The Modified Chaplygin Gas (MCG) model belongs to the class of a unified models of dark energy and dark matter. In this paper, we have modeled MCG in the framework of f-essence cosmology. By constructing an equation connecting the MCG and the f-essence, we solve it to obtain explicitly the pressure and energy density of MCG. As special cases, we obtain both positive and negative pressure solutions for suitable choices of free parameters. We also calculate the state parameter which describes the phantom crossing.Comment: 12 pages, (Invited Review), accepted for publication in "Astrophysics and Space Science" DOI: 10.1007/s10509-011-0870-