bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of atomoxetine in children and adolescents with ADHD
Authors: Banerjee Somnath
Published: April 2009

Atomoxetine is a non‐stimulant drug licensed for use in the treatment of attention deficit‐hyperactivity disorder (ADHD).Dr Banerjee describes a study that was carried out over a two‐year period in the three ADHD clinics in East Kent Hospitals NHS Trust to evaluate the current practice on the use of atomoxetine in ADHD in children and adolescents. Copyright © 2009 Wiley Interface Ltd
In prostate cancer C/EBPα promotes cell growth by the loss of interactions with CDK2, CDK4, and E2F and by activation of AKT
Authors: Yin Hong , Lowery Mary , Glass Jonathan
Published: April 2009

BACKGROUND

The CCAAT/Enhancer binding protein alpha (C/EBPα) is an important transcription factor for granulopoiesis and adipogenesis. While decreased expression and mutation of C/EBPα has been found in several types of tumors, the role of C/EBPα in prostate cancer has not been well characterized.

METHODS

We quantitatively analyzed the immunochemical staining of prostate cancer tissue and examined the growth properties of prostate cancer cells stably expressing C/EBPα by measure growth curve, cell cycle, and anchorage independent colony formation, investigated the association of C/EBPα with E2Fs and CDKs by co‐immunoprecipitation and examined the expression of CDKs and activation of AKT by Western blot analysis.

RESULTS

The ratio of C/EBPα expression between cancer cells close to the pseudolumen of glands and those nearer the basal cell layer was more than threefold greater than that seen in the normal prostate epithelium. Further, this ratio increased with increased Gleason score of the prostate cancer. Forced expression of C/EBPα in prostate cancer cell lines accelerated cell growth, stimulated cells into the S and G2 phases of cell cycle, and enhanced anchorage‐independent colony formation. Simultaneously, forced expression of C/EBPα increased expression of CDK2/CDK4 and nuclear PP2A, and activated AKT. In addition, C/EBPα was no longer found associated with E2F1/E2F4 and CDK2/CDK4. AKT and PPA2 inhibitors restored both the anti‐proliferation function of C/EBPα and the interaction between C/EBPα and E2F1/E2F4.

CONCLUSION

In prostate cancer cells C/EBPα cannot function as a tumor suppressor. Prostate 69: 1001–1016, 2009. © 2009 Wiley‐Liss, Inc.
Status epilepticus: features and appropriate management
Authors: Silver Nicholas , Cockerel Charles
Published: April 2009

Status epilepticus represents a medical emergency and is associated with significant morbidity and mortality. The authors describe the clinical features and recommended treatment. Copyright © 2009 Wiley Interface Ltd
Entanglement swapping in presence of dephasing
Authors: Dajka J. , Łuczka J. , Hänggi P.
Published: April 2009

Entanglement which originates from a pair of non‐interacting qubits by means of entanglement swapping is discussed when dephasing mechanisms are present. Then, the exact reduced dynamics can be evaluated for two pairs of independent qubits which each are coupled to their own bosonic environment. Each of two pairs of qubits is initially maximally entangled. The conditions for the entanglement survival at asymptotic long times in terms of environment spectral properties are elaborated. It is shown that these conditions hold true also for the inter–pair entanglement stemming. Entanglement swapping can effectively been controlled by a proper choice of initial state of the finite environment (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron pair current through the correlated quantum dot
Authors: Domański T. , Donabidowicz A.
Published: April 2009

We study the charge current transmitted through the correlated quantum dot characterized by a finite magnitude of the Coulomb interaction |U |. At low temperatures the correlations can lead to a formation of the spin (for U > 0) or charge (for U < 0) Kondo states which qualitatively affect the transport properties. We explore the influence of charge Kondo effect on the electron pair tunneling introducing the auxiliary two‐channel model accounting for the fluctuations between the empty and doubly occupied states on QD (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Friedel oscillations in the presence of far from equilibrium heat transport
Authors: Gorczyca A. , Maśka M. M. , Mierzejewski M.
Published: April 2009

We investigate an inhomogeneous one‐dimensional nanosystem coupled to macroscopic leads of different temperatures. In particular, we consider a system with an impurity with on‐site scattering potential located in the middle of the nanowire. Such an impurity produces oscillations of the density of carriers in its vicinity, the so‐called Friedel oscillations.

In the equilibrium case these oscillations are symmetric with respect to the position of the impurity. Here, we demonstrate that strongly asymmetric Friedel oscillations occur if the system is far from the equilibrium. We discuss how this asymmetry depends on the model parameters and the difference of the temperatures of the leads (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inverse probability‐of‐censoring weights for the correction of time‐varying noncompliance in the effect of randomized highly active antiretroviral therapy on incident AIDS or death
Authors: Cain Lauren E. , Cole Stephen R.
Published: April 2009

In 1996–1997, the AIDS Clinical Trial Group 320 study randomized 1156 HIV‐infected U.S. patients to combination antiretroviral therapy (ART) or highly active ART with equal probability. Ninety‐six patients incurred AIDS or died, 51 (4 per cent) dropped out, and 290 (=51 + 239, 25 per cent) dropped out or stopped their assigned therapy for reasons other than toxicity during a 52‐week follow‐up. Such noncompliance likely results in null‐biased estimates of intent‐to‐treat hazard ratios (HR) of AIDS or death comparing highly active ART with combination ART, which were 0.75 (95 per cent confidence limits [CL]: 0.43, 1.31), 0.30 (95 per cent CL: 0.15, 0.60), and 0.51 (95 per cent CL: 0.33, 0.77) for follow‐up within 15 weeks, beyond 15 weeks, and overall, respectively. Noncompliance correction using Robins and Finkelstein's (RF) inverse probability‐of‐censoring weights (where participants are censored at dropout or when first noncompliant) yielded estimated HR of 0.46 (95 per cent CL: 0.25, 0.85), 0.43 (95 per cent CL: 0.19, 0.96), and 0.45 (95 per cent CL: 0.27, 0.74) for follow‐up within 15 weeks, beyond 15 weeks, and overall, respectively. Weights were estimated conditional on measured age, sex, race, ethnicity, prior Zidovudine use, randomized arm, baseline and time‐varying CD4 cell count, and time‐varying HIV‐related symptoms. Noncompliance corrected results were 63 and 13 per cent farther from the null value of one than intent‐to‐treat results within 15 weeks and overall, respectively, and resolve the apparent non‐proportionality in intent‐to‐treat results. Inverse probability‐of‐censoring weighted methods could help to resolve discrepancies between compliant and noncompliant randomized evidence, as well as between randomized and observational evidence, in a variety of biomedical fields. Copyright © 2009 John Wiley & Sons, Ltd.
Horizontal alliances as an alternative to autonomous production: product expansion mode choice in the worldwide aircraft industry 1945–2000
Authors: Garrette Bernard , Castañer Xavier , Dussauge Pierre
Published: April 2009

This study investigates why firms choose to undertake product expansion through alliances with competitors rather than on their own. We highlight product heterogeneity as a determinant of this make or ally choice. We propose that firms turn to horizontal alliances in order to implement product expansion projects that require greater resources than those available to them. More precisely, we hypothesize that a firm is more likely to launch a new product through a horizontal alliance rather than autonomously when the resource requirements of the project are greater, the resources available to the firm are more limited, there is a mismatch between resource endowment and requirement, and the firm's collaborative competence allows it to better cope with the interorganizational concerns that collaboration with competitors raises. We find support for our arguments on a sample of 310 new aircraft developments launched between 1945 and 2000, either by a single prime contractor or as a horizontal alliance in which prime contractorship is shared with another industry incumbent. Copyright © 2009 John Wiley & Sons, Ltd.
The Role of PTIP in Maintaining Embryonic Stem Cell Pluripotency
Authors: Kim Doyeob , Patel Sanjeevkumar R. , Xiao Hong , Dressler Gregory R.
Published: April 2009

Pax transactivation domain-interacting protein (PTIP) is a ubiquitously expressed, nuclear protein that is part of a histone H3K4 methyltransferase complex and is essential for embryonic development. Methylation of H3K4 is an epigenetic mark found on many critical developmental regulatory genes in embryonic stem (ES) cells and, together with H3K27 methylation, constitutes a bivalent epigenetic signature. To address the function of PTIP in ES cells, we generated ES cell lines from a floxed ptip allele and deleted PTIP function with Cre recombinase. The ptip−/− ES cell lines exhibited a high degree of spontaneous differentiation to trophectoderm and a loss of pluripotency. Reduced levels of Oct4 expression and H3K4 methylation were observed. Upon differentiation, ptip−/− embryoid bodies showed reduced levels of marker gene expression for all three primary germ layers. These results suggest that the maintenance of H3K4 methylation is essential and requires PTIP function during the in vitro propagation of pluripotent ES cells.

Disclosure of potential conflicts of interest is found at the end of this article.
Trafficking Mesenchymal Stem Cell Engraftment and Differentiation in Tumor-Bearing Mice by Bioluminescence Imaging
Authors: Wang Hui , Cao Feng , De Abhijit , Cao Yuan , Contag Christopher , Gambhir Sanjiv S. , Wu Joseph C. , Chen Xiaoyuan
Published: April 2009

The objective of the study was to track the distribution and differentiation of mesenchymal stem cells (MSCs) in tumor-bearing mice. The 4T1 murine breast cancer cells were labeled with renilla luciferase-monomeric red fluorescence protein (rLuc-mRFP) reporter gene. The MSCs labeled with firefly luciferase-enhanced green fluorescence protein (fLuc-eGFP) reporter gene (MSCs-R) were isolated from L2G85 transgenic mice that constitutively express fLuc-eGFP reporter gene. To study the tumor tropism of MSCs, we established both subcutaneous and lung metastasis models. In lung metastasis tumor mice, we injected MSCs-R intravenously either on the same day or 4 days after 4T1 tumor cell injection. In subcutaneous tumor mice, we injected MSCs-R intravenously 7 days after subcutaneous 4T1 tumor inoculation. The tumor growth was monitored by rLuc bioluminescence imaging (BLI). The fate of MSCs-R was monitored by fLuc BLI. The localization of MSCs-R in tumors was examined histologically. The osteogenic and adipogenic differentiation of MSCs-R was investigated by alizarin red S and oil red O staining, respectively. The mechanism of the dissimilar differentiation potential of MSCs-R under different tumor microenvironments was investigated. We found that the 4T1 cells were successfully labeled with rLuc-mRFP. The MSCs-R isolated from L2G85 transgenic mice constitutively express fLuc-eGFP reporter gene. When injected intravenously, MSCs-R survived, proliferated, and differentiated in tumor sites but not elsewhere. The localization of GFP+ MSCs-R in tumor lesions was confirmed ex vivo. In conclusion, the MSCs-R can selectively localize, survive, and proliferate in both subcutaneous tumor and lung metastasis as evidenced by noninvasive bioluminescence imaging and ex vivo validation. The MSCs-R migrated to lung tumor differentiated into osteoblasts, whereas the MSCs-R targeting subcutaneous tumor differentiated into adipocytes.

Disclosure of potential conflicts of interest is found at the end of this article.
Transplantation of Embryonic and Adult Neural Stem Cells in the Granuloprival Cerebellum of the Weaver Mutant Mouse
Authors: Chen K. Amy , Lanuto Derek , Zheng Tong , Steindler Dennis A.
Published: April 2009

Numerous studies have explored the potential of different stem and progenitor cells to replace at-risk neuronal populations in a variety of neurodegenerative disease models. This study presents data from a side-by-side approach of engrafting two different stem/progenitor cell populations within the postnatal cerebellum of the weaver neurological mutant mouse—cerebellar-derived multipotent astrocytic stem cells and embryonic stem cell–derived neural precursors—for comparative analysis. We show here that both donor populations survive, migrate, and appear to initiate differentiation into neurons within the granuloprival host environment. Neither of these disparate stem/progenitor cell populations adopted significant region-specific identities, despite earlier studies that suggested the potential of these cells to respond to in vivo cues when placed in a permissive/instructive milieu. However, data presented here suggest that molecular and cellular deficits present within weaver homozygous or heterozygous brains may promote a slightly more positive donor cell response toward acquisition of a neuronal phenotype. Hence, it is likely that a fine balance exists between a compromised host environment that is amenable to cell replacement and that of a degenerating cellular milieu where it is perhaps too deleterious to support extensive neuronal differentiation and functional cellular integration. These findings join a growing list of studies that show successful cell replacement depends largely on the interplay between the potentiality of the donor cells and the specific pathological conditions of the recipient environment, and that emergent therapies for neurological disorders involving the use of neural stem cells still require refinement.

Disclosure of potential conflicts of interest is found at the end of this article.
Embryonic Stem Cell-Derived Cardiomyogenesis: A Novel Role for Calreticulin as a Regulator
Authors: Papp Sylvia , Dziak Ewa , Opas Michal
Published: April 2009

A role for calreticulin, an endoplasmic reticulum (ER)-resident, Ca2+-binding chaperone, has recently emerged in the context of cardiomyogenesis. We previously proposed calreticulin to be a novel cardiac fetal gene, because calreticulin knockout causes embryonic lethality in mice as a result of cardiac defects, it is transiently activated during heart development, and heart-targeted overexpression of constitutively active calcineurin in calreticulin-null mice rescues the lethal phenotype. Calreticulin affects Ca2+ homeostasis and expression of adhesion-related genes. Using cardiomyocytes derived from both calreticulin-null and wild-type embryonic stem (ES) cells, we show here that cardiomyogenesis from calreticulin-null ES cells is accelerated but deregulated, such that the myofibrils of calreticulin-null cardiomyocytes become disorganized and disintegrate with time in culture. We have previously shown that the disorganization of the actin cytoskeleton in calreticulin-null cells may be explained, at least in part, by the downregulation of adhesion proteins, implying that calreticulin ablation causes adhesion-related defects. Here, upon examination of adhesion proteins, we found that vinculin is downregulated in calreticulin-null cardiomyocytes. We also found c-Src activity to be higher in calreticulin-null cardiomyocytes than in wild-type cardiomyocytes, and c-Src activity is affected by both calreticulin and [Ca2+]. Finally, we show that calreticulin and calsequestrin, the major Ca2+ storage proteins of the ER and sarcoplasmic reticulum, respectively, exhibit alternate distributions. This suggests that calreticulin may have a housekeeping role to play in mature cardiomyocytes as well as during cardiomyogenesis. We propose here that calreticulin, an ER Ca2+ storage protein, is a crucial regulator of cardiomyogenesis whose presence is required for controlled cardiomyocyte development from ES cells.

Disclosure of potential conflicts of interest is found at the end of this article.
Endo‐Laparoscopic Colectomy Without Mini‐Laparotomy for Left‐Sided Colonic Tumors
Authors: Cheung Hester Y. S. , Leung Alex L. H. , Chung C. C. , Ng Dennis C. K. , Li Michael K. W.
Published: April 2009

Background

In performing “traditional” laparoscopic colectomy for left‐sided colonic tumors, specimen retrieval necessitates a mini‐laparotomy which often is the cause of postoperative pain, wound infection, and other pain‐related complications. Here we describe a new technique of endo‐laparoscopic anterior resection without mini‐laparotomy, where specimen retrieval and colorectal anastomosis can be safely achieved with the use of the transanal endoscopic operation (TEO) device set‐up.

Methods

This hybrid natural orifice transluminal endoscopic surgery (NOTES) technique involves insertion of the TEO device in the lower rectum and luminal extraction of the specimen via the device. The technique is applicable to patients with small tumors (4 cm or less) in the left‐sided colon or upper rectum, where transanal construction of a stapled colorectal anastomosis is intended.

Results

The technique was attempted in ten patients (male:female 4:6) with median age of 66 years (range: 55–81 years). Five patients suffered from rectosigmoid tumors, whereas four patients had lesions in the sigmoid colon and one had a lesion in the descending colon. The median operating time was 127.5 min (range: 105–170 min) and the median blood loss was 20 ml (range: 20–50 ml). The median hospital stay was 7 days (range: 4–18 days), while the median maximum pain score (visual analog score) was 2 (range: 2–3) during in‐hospital stay in this small series.

Conclusions

Our preliminary experience indicates this new technique of endo‐laparoscopic colectomy is feasible for selected patients with left‐sided colonic tumors. Complications related to mini‐laparotomy can be abolished entirely with this hybrid approach.
Universal Precautions and Surgery in Sierra Leone: The Unprotected Workforce
Authors: Kingham T. Peter , Kamara T. B. , Daoh K. S. , Kabbia Soccoh , Kushner Adam L.
Published: April 2009

Background

Surgical patients and healthcare workers in sub‐Saharan Africa are at an increased risk of contracting HIV. Sierra Leone is one of the poorest countries in the world and has a documented HIV prevalence rate of 2%. Because surgeons and other healthcare staff in sub‐Saharan Africa are at risk for HIV exposure from their patients, an assessment of protective supplies and equipment was considered essential.

Methods

A Society of International Humanitarian Surgeons team in cooperation with the Sierra Leonean Ministry of Health and Sanitation undertook a survey of HIV‐protective supplies and equipment at government hospitals in Sierra Leone. The presence of eye protection, sterile gloves, aprons, functioning suction machines, and sharps containers was recorded and compared with a local mission hospital and a local private hospital.

Results

Only 20% of government hospitals in Sierra Leone have adequate stores of sterile gloves or eye protection. Suction pumps and aprons are available in only 30–40% of facilities, respectively, and only half have functioning sterilizers and sharps containers. The mission and private hospitals were fully stocked.

Conclusions

Although surgical healthcare workers are at risk for exposure to HIV, resources for their protection at government hospitals in Sierra Leone are severely lacking. The Society of International Humanitarian Surgeons is developing a program to provide protective supplies and equipment to hospitals in Sierra Leone, but additional efforts by other organizations working to decrease the spread of HIV are essential.
Effect of Preoperative Hyperfibrinogenemia on Recurrence of Colorectal Cancer Without a Systemic Inflammatory Response
Authors: Yamashita Hiroharu , Kitayama Joji , Taguri Masataka , Nagawa Hirokazu
Published: April 2009

Background

Disorders in the blood coagulation system are often associated with malignancy. Patients with colorectal cancer (CRC) have been shown to have abnormal data for various coagulation tests.

Methods

We retrospectively analyzed the relation between the preoperative plasma fibrinogen level and tumor recurrence in 569 patients with CRC who underwent curative surgical resection and were followed up without adjuvant chemotherapy.

Results

The plasma fibrinogen level showed a positive association with tumor recurrence, age, sex, T stage, and TNM classification. When divided with the median value, hyperfibrinogenemia is positively correlated with tumor recurrence, although it lost independence in the multivariate analysis. In the C‐reactive protein (CRP)‐negative population, hyperfibrinogenemia is independently correlated with tumor recurrence and recurrence‐free survival. In contrast, hyperfibrinogenemia has no effect on recurrence in CRP‐positive patients.

Conclusions

Hyperfibrinogenemia is clinically relevant in tumor recurrence before a systemic inflammatory response and thus can be a useful predictor of recurrence in the preinflammatory stage of CRC.
Regularized Generalized Structured Component Analysis
Authors: Hwang Heungsun
Published: March 2009

Generalized structured component analysis (GSCA) has been proposed as a component-based approach to structural equation modeling. In practice, GSCA may suffer from multi-collinearity, i.e., high correlations among exogenous variables. GSCA has yet no remedy for this problem. Thus, a regularized extension of GSCA is proposed that integrates a ridge type of regularization into GSCA in a unified framework, thereby enabling to handle multi-collinearity problems effectively. An alternating regularized least squares algorithm is developed for parameter estimation. A Monte Carlo simulation study is conducted to investigate the performance of the proposed method as compared to its non-regularized counterpart. An application is also presented to demonstrate the empirical usefulness of the proposed method.
Selective block of tunneling nanotube (TNT) formation inhibits intercellular organelle transfer between PC12 cells
Authors: Bukoreshtliev Nickolay V. , Wang Xiang , Hodneland Erlend , Gurke Steffen , Barroso João F.V. , Gerdes Hans-Hermann
Published: April 2009

Organelle exchange between cells via tunneling nanotubes (TNTs) is a recently described form of intercellular communication. Here, we show that the selective elimination of filopodia from PC12 cells by 350 nM cytochalasin B (CytoB) blocks TNT formation but has only a weak effect on the stability of existing TNTs. Under these conditions the intercellular organelle transfer was strongly reduced, whereas endocytosis and phagocytosis were not affected. Furthermore, the transfer of organelles significantly correlated with the presence of a TNT‐bridge. Thus, our data support that in PC12 cells filopodia‐like protrusions are the principal precursors of TNTs and CytoB provides a valuable tool to selectively interfere with TNT‐mediated cell‐to‐cell communication.
ON THE LARGEST PRIME FACTOR OF THE MERSENNE NUMBERS
Authors: FORD KEVIN , LUCA FLORIAN , SHPARLINSKI IGOR E.
Published: April 2009

LetP(k) be the largest prime factor of the positive integerk. In this paper, we prove that the seriesis convergent for each constantα<1/2, which gives a more precise form of a result of C. L. Stewart [‘On divisors of Fermat, Fibonacci, Lucas and Lehmer numbers’,Proc. London Math. Soc.35(3) (1977), 425–447].
QUALIFIED DIFFERENCE SETS FROM UNIONS OF CYCLOTOMIC CLASSES
Authors: BYARD KEVIN , BROUGHAN KEVIN
Published: April 2009

Qualified difference sets (QDS) composed of unions of cyclotomic classes are discussed. An exhaustive computer search for such QDS and modified QDS that also possess the zero residue has been conducted for all powers n=4,6,8 and 10. Two new families were discovered in the case n=8 and some new isolated systems were discovered for n=6 and n=10.
Placement of fertilizer for potatoes
Authors: Cooke G. W.
Published: March 2009

In twenty-nine experiments conducted in 1945, 1946 and 1947 placement of fertilizer in contact with the seed or in two bands each 2 in. away and 2 in. below the level of the seed gave average yields similar to those given by the standard practice of broadcasting after ridging but before planting. Placement in one band 2 in. below the seed was tested in four experiments and proved inferior to other placement methods and to broadcasting over the ridges.
Effects of separation, dilution, washing and acidification on ammonia volatilization from surface-applied cattle slurry
Authors: Stevens R. J. , Laughlin R. J. , Frost J. P.
Published: March 2009

Treatments which lowered the rate of ammonia volatilization from surface-applied cattle slurry were evaluated in three field experiments during 1989/90 at the Agricultural Research Institute of Northern Ireland. The relative effects of separation, dilution with water before application and washing with a water spray after application, on ammonia volatilization rates were compared over 4 days using ventilated enclosures. As the loss rate of ammonia during the first 4 days after application was highly correlated with the loss rate over the first 4 hours after application, the loss rate in the first 4 hours was used as a rapid method to assess the efficacy of various combinations of separation, dilution and acidification. Ammonia volatilization loss rates from treatment combinations were compared to the loss rate from whole slurry.

A 50% decrease in ammonia volatilization was achieved by separation through a 0·4 mm mesh, separation through a 10·0 mm mesh plus dilution with 86% by volume of water, or separation through a 2·0 mm mesh plus washing with 53% by volume of water.

A 75% decrease in ammonia volatilization was achieved by acidification to pH 6·5, or combinations of separation and dilution, namely separation through a 0·4 mm mesh plus 50% dilution or separation through a 5·0 mm mesh plus 100% dilution.

A 90% decrease in ammonia volatilization was achieved by acidification to pH 6·0, dilution by 50% plus acidification to pH 6·5, or separation through a 0·4 mm mesh plus acidification to pH 6·5.

The effects of separation and acidification on ammonia volatilization were cumulative. There was a highly significant inverse linear relationship between ammonia volatilization rate and volume of nitric acid used. Adding 10 M nitric acid at 1·4% by volume lowered volatilization by 75% of that from whole slurry and increased the nitrogen content of the slurry by 2 g N/l, making it a more balanced NPK fertilizer for cut swards. Because the variable value of cattle slurry is due to loss of nitrogen as ammonia and smothering of the sward with slurry solids, a combination of separation or dilution to lower sward contamination and acidification with nitric acid to lower volatilization may be the best practical option for improving cattle slurry as a fertilizer for cut grass.
Energy requirements of the pregnant ewe
Authors: Russel A. J. , Doney J. M. , Reid R. L.
Published: March 2009

Fifty-one Scottish Blackface ewes were divided into three groups and individually fed throughout the latter half of pregnancy: (I) in excess of their nutrient requirements, (II) to produce a uniformly moderate degree of undernourishment throughout the final 6 weeks of pregnancy, and (III) to produce a uniformly severe degree of undernourishment during the same period.

Marked differences were evident in the amounts of feed required to maintain the prescribed nutritional states, and within the undernourished groups, between ewes with single and twin foetuses. In both groups of undernourished ewes the amount of feed required to maintain the prescribed level of undernourishment during late pregnancy was strongly related (P < 0·001) to birth-weight. The additional nutrient requirement of the ewe in late pregnancy was estimated to be 100 g D.o.m./kg foetus/day.
The relative importance of embryo size and endosperm size in causing the effects associated with seed size in wheat
Authors: Bremner P. M. , Eckersall R. N. , Scott R. K.
Published: March 2009

1. The growth of wheat plants at two depths of planting, from seed in which embryo size and endosperm size were varied independently was studied.

2. Embryo size was shown to have a negligible effect on growth, whilst endosperm size had a considerable effect; the influence of neither embryosize nor endosperm size appeared to be in any way modified by depth of planting. It is suggested that the relationship between seed size and plant size is governed by the amount of reserve material present in the seed.

3. During the first 6 days of growth small embryos had a higher relative growth rate than large ones, apparently regardless, within wide limits, of the amount of reserve material in the seed. Thereafter until the exhaustion of reserves growth appeared to be related to the amount of reserve material present.
Survival and fertility of bovine sperm kept at variable temperatures in coconut milk extender
Authors: Norman C. , Johnson C. E. , Porterfield I. D. , Goldberg E. , Dunbar R. S. , Min H. S. , Dunn H. O.
Published: March 2009

Bovine spermatozoa aged for 6–7 days at room temperatures (18–30° C.) in a coconut milk extender retained their fertilizing capacity. However, their fertilizing ability appeared to be impaired by environmental hazards in the form of oxygen damage, exposure to visible light, and temperature shock. Protective measures developed and used in the preparation and in the storage of the sperm suspensions to minimize premature loss of sperm function involved the addition of catalase and egg yolk to the extender and the maintenance of cell suspensions in the dark in vials containing a minimal air space. The experimental evidence obtained with this improved coconut milk extender established its ability to support and sustain the fertilizing capacity of bovine sperm for 6–7 days at room temperatures at a level comparable to the fertilizing capacity of refrigerated sperm in milk-glycerol or egg yolk-citrate-glycine extenders. The economic importance of this room temperature diluent is suggested by the fact that it eliminates the costly refrigeration required to maintain stored and shipped bovine semen at 5° C.

Coconut milk extender modified by the addition of 5% egg yolk also proved to be a satisfactory storage medium for sperm at low temperatures. It was found to be superior to both egg yolk-citrate and skim-milk extenders in conserving motility at 5° C. The fertilizing capacity of Ayrshire and Brown Swiss sperm stored at 5° C. in coconut milk extender which contained 15% coconut milk and 5% egg yolk compared favourably with the fertilizing capacity reported for sperm stored at 5° C. in other more widely used diluents. The number of motile sperm recovered from this extender after freezing to −79° C. was comparable to the number of motile sperm recovered from the egg yolk-citrate and skim-milk test diluents. The results of this study indicate that coconut milk extender is a versatile, easily prepared medium which can be used to preserve functional sperm over a wide temperature range.
A note on the use of the analysis of covariance to reduce standard errors in experiments on milk production
Authors: Broster W. H. , Curnow R. N.
Published: March 2009

The use of changeover designs and of covariance analysis in experiments on lactating cows is reviewed. Continuous treatment designs are criticized because of their large coefficients of variation, e.g. of the order of 20 % for milk yield. Although changeover designs have smaller errors they are criticized because the results have strictly limited practical application. Covariance analysis applied to the data from continuous treatment designs offers a means of increasing their precision. Measurements made in a preliminary period may be used to adjust experimental measurements made subsequently for animal to animal variation. The covariance method was tested on data from thirtytwo heifers in an experiment involving factorial sequences of treatments. Weeks 5-12 of lactation formed the control period and weeks 13-22 the experimental period.
Soil water use and growth of a grass sward
Authors: Garwood E. A. , Williams T. E.
Published: March 2009

1. The rate and pattern of water extraction from the soil by grass swards were examined.

2. Under a continued drought water was removed progressively down the soil profile. The rate of removal of water was similar from all horizons to a depth of over 3 ft in these conditions.
Milking performance of Blanco Orejinegro and Jersey crossbred cattle
Authors: Pearson Lucia , Waugh R. K. , Salazar Bernardo , Botero F. M. , Acosta O.
Published: March 2009

Samples of a Colombian criollo breed of cattle, the Blanco Orejinegro, and contemporary onequarter Jersey crossbreds were kept on a farm in the Andes. Records were included of all calvings which occurred over an 8-year period, giving totals of 1357 lactations from 514 purebreds and 424 lactations from 137 crossbreds.

Age at first calving was about 41 months for both breed groups. Cattle were milked twice daily by hand without calf at foot. Mean lactation yields were 220 kg (purebreds) and 612 kg (crossbreds). The repeatability and heritability of milk yield are estimated. Statistics are also given for lactation length, daily yield, calving interval and butterfat percentage. The effects on yield of age at first calving and calving year were negligible, but month of calving was important.

It is concluded that the low level of performance was partly due to failure to eject milk without calf at foot, at least in the case of the purebreds, and that this was itself mainly due to genetic causes. The improvement in yield due to crossbreeding was not accompanied by a loss of other desirable traits. The development of the local cattle industry is discussed in the light of these results and the general characteristics of the region.
Effect of flushing on reproductive performance of ewes
Authors: Coop I. E.
Published: March 2009

Eight flushing experiments were conducted with grazing sheep over a 4-year period, the responses being measured at lambing. In the first 2 years mobs of 600-750 ewes were employed. Those experiments were designed to separate, identify and measure the two components postulated as comprising the flushing response—a static live-weight effect not specifically related in time to the mating period, and a dynamic effect of the rising or falling body condition which is specific to the mating period.
Statistical research on the fate of water in the adult cow. I. Dry cows
Authors: Paquay R. , Baere R. De , Lousse A.
Published: March 2009

Statistical analyses were carried out on the data obtained, under strictly controlled conditions in metabolism stalls, from 219 adult non-pregnant dry cows fed on seventyone different rations. The authors have calculated and studied the correlations between total water intake, faecal and urinary water losses, absorbed and available water, and the seventy-five other factors which were analysed in each of the seventy-one rations. Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements.

Total water intake closely correlated with the dry-matter intake and also with the dry-matter content of the diet; forages with high moisture content enhance the total water intake which is also significantly correlated to the intake of nitrogen, fat and some mineral elements.

Faecal water losses are strongly correlated with the dry-matter intake and on the faecal dry matter. Moisture content of the diet has no significant effect but increasing pentosans and crude-fibre intake enhance the losses.

Urinary water excretion is closely related to the amount of absorbed water and to the dry-matter content of the diet; a highly significant correlation also exists between urinary water and urinary nitrogen and potassium. The amount of water excreted in the urine may affect the utilization of digestible nitrogen and potassium.

Available water is increased logarithmically when total water intake rises arithmetically. Feeds with high moisture content thus enhance the amount of available water.
A preliminary study of protein requirements of African cattle
Authors: Elliott R. C.
Published: March 2009

1. A preliminary study of the protein requirements of young steers of two breeds of African cattle has been described. These requirements were assessed by studying body weight changes of groups of animals fed for 140 days on rations varying in protein content.

2. There were only small differences between the breeds in their voluntary food intake while appetite seemed to be linearly related to protein content.

3. The two breeds were equally efficient in food and protein utilization.

4. Live-weight gain improved significantly as the protein content of the ration increased from 6 to 10%, but a further increase to 14% produced only a small subsequent improvement in growth.

5. Maintenance of weight was estimated to occur at a digestible protein intake of only 48% of that recommended by Brody (1945), while the required digestible protein for one pound daily gain was in agreement with the National Research Council (1950) standard.
Quantitative observations on pig embryos of known ages
Authors: Marrable A. W. , Ashdown R. R.
Published: March 2009

1. The lengths and weights of 241 pig embryos, aged 26–109 days, were recorded; the pregnant sows were from a mixed herd of Landrace, Large White and Wessex stock and some of their crosses.

2. An empirical linear regression of length on age was estimated (equation 1); the relation between weight and age was represented by a polynomial weight and age was represented by a polynomial (equation 2).

We thank Mr A. S. Cray and the other directors of Unigate Ltd. for giving us the pigs; Mr P. Sedgewick of that Company gave us excellent co-operation. Prof. C. W. Ottaway and Dr P. Radford helped us throughout the investigation.
Body composition of young sheep: II. Effect of stocking rate on body composition of Dorset Horn cross lambs
Authors: Arnold G. W. , Gharaybeh H. R. , Dudzinski M. L. , McManus W. R. , Axelsen A.
Published: March 2009

Empty body weight and body measurements were made on 142 lambs from Border Leicester × Merino and Merino ewes mated to Dorset Horn rams, grazed at three stocking rates and slaughtered at approximately 32·3 kg full body weight (FBW). Carcass composition studies were made on 58 of these lambs. An approximate doubling of growth rate during the first 6 weeks of life occurred between stocking rates for lambs from Merino ewes. A smaller difference was found in lambs from Border Leicester × Merino ewes. Growth rates of lambs from Merinos were significantly lower at all times from birth to slaughter. Stocking rate, breed and sex effects on growth rate resulted in lambs reaching mean weight of 32·3 kg at 80–150 days.

A three-way analysis of variance was performed on data for all parameters measured using FBW as a covariate. These parameters were of carcass measurements and composition, and of composition of the internal organs. There were no effects of stocking rate on empty body weight, carcass weight, or any carcass measurements. The weight of dry edible meat was depressed at the high stocking rate due to a higher moisture content. The fresh weight of internal organs was lower at the high stocking rate. A number of sex differences were found. Ewes had lighter carcasses and heavier cannon bones; their edible meat had a higher moisture content and higher ash content than wethers. Eye muscle width was less in ewes than in wethers. Internal organs of ewes had a lower EE % and higher CP % than those of wethers. The only breed type differences were in the weights of internal organs and eye muscle widths at the 9–10th and lOth–llth ribs, and age to slaughter.
Observations on the calcium balance of laying hens
Authors: Hurwitz S. , Griminger P.
Published: March 2009

Two groups of Single Comb White Leghorn pullets, 4 months of age, were fed 1·85 and 2·70% calcium in the diet, respectively, for twelve consecutive periods, each consisting of 4 weeks.

Records of egg production and egg weight were kept throughout the entire experiment for each hen. Calcium balance and egg-shell quality studies were conducted with 16 pullets for 5 consecutive days out of each 28-day period.

A highly significant difference between the lots favouring the high-calcium birds was found in egg production, shell weight, and calcium retention. There were no significant differences between the lots in percentage calcium retention, food consumption, and body weight. The high-calcium group was shown to retain more calcium from the feed and excrete more calcium through eggs. Calcium retention and percentage calcium retention increased upon commencement of egg production to reach a maximum at the second period of production. Both remained fairly constant thereafter.

The hens went into negative balance early in production and returned to positive balance during the later part of the first laying year. The return to positive balance could be explained by an increase in calcium retention and a decrease in egg production. There was no reduction in shell weight, or shell weight per unit surface area during the period covered by this trial.
Determination of nitrogen in soil by the Kjeldahl method
Authors: Bremner J. M.
Published: March 2009

1. The reliability of the Kjeldahl method for the determination of nitrogen in soils has been investigated using a range of soils containing from 0·03 to 2·7% nitrogen.

2. The same result was obtained when soil was analysed by a variety of Kjeldahl procedures which included methods known to recover various forms of nitrogen not determined by Kjeldahl procedures commonly employed for soil analysis. From this and other evidence presented it is concluded that very little, if any, of the nitrogen in the soils examined was in the form of highly refractory nitrogen compounds or of compounds containing N—N or N—O linkages.

3. Results by the method of determining nitrogen in soils recommended by the Association of Official Agricultural Chemists were 10–37% lower than those obtained by other methods tested. Satisfactory results were obtained by this method when the period of digestion recommended was increased.

4. Ammonium-N fixed by clay minerals is determined by the Kjeldahl method.

5. Selenium and mercury are considerably more effective than copper for catalysis of Kjeldahl digestion of soil. Conditions leading to loss of nitrogen using selenium are defined, and difficulties encountered using mercury are discussed.

6. The most important factor in Kjeldahl analysis is the temperature of digestion with sulphuric acid, which is controlled largely by the amount of potassium (or sodium) sulphate used for digestion.

7. The period of digestion required for Kjeldahl analysis of soil depends on the concentration of potassium sulphate in the digest. When the concentration is low (e.g. 0·3 g./ml. sulphuric acid) it is necessary to digest for several hours; when it is high (e.g. 1·0 g./ml. sulphuric acid) short periods of digestion are adequate. Catalysts greatly affect the rate of digestion when the salt concentration is low, but have little effect when the salt concentration is high.

8. Nitrogen is lost during Kjeldahl analysis when the temperature of digestion exceeds about 400° C.

9. Determinations of the amounts of sulphuric acid consumed by various mineral and organic soils during Kjeldahl digestion showed that there is little risk of loss of nitrogen under the conditions usually employed for Kjeldahl digestion of soil. Acid consumption values for various soil constituents are given, from which the amounts of sulphuric acid likely to be consumed during Kjeldahl digestion of different types of soil can be calculated.

10. Semi-micro Kjeldahl methods of determining soil nitrogen gave the same results as macro-Kjeldahl methods.

11. The use of the Hoskins apparatus for the determination of ammonium is described.

12. It is concluded that the Kjeldahl method is satisfactory for the determination of nitrogen in soils provided a few simple precautions are observed. The merits and defects of different Kjeldahl procedures are discussed.
The effects of magnesium fertilizers on yield and chemical composition of sugar beet
Authors: Draycott A. P. , Durrant M. J.
Published: March 2009

Nineteen experiments were made between 1964 and 1967 on fields where previous sugar beet crops showed symptoms of magnesium deficiency. None, 2·5 or 5 cwt/acre kieserite or 20 cwt/acre dolomitic limestone were tested in a factorial design with none or 3 cwt/acre agricultural salt (crude sodium chloride), and 0.8 or 1.2 cwt/acre nitrogen as ‘Nitro-Chalk’. Additional plots tested kainit (7 cwt/acre) and a large dressing of potash (2 cwt/acre) as muriate of potash.

Kieserite and dolomitic limestone increased sugar yield and the most effective dressing was 5 cwt/acre kieserite, which gave 3·1 cwt/acre more sugar than the crop without magnesium fertilizer. Agricultural salt and the larger dressing of nitrogen were profitable, and neither interacted with magnesium on average; the large dressing of potash also increased yield. The magnesium in the kainit increased yield slightly, but the dressing tested supplied too little to satisfy the crop's requirement of magnesium.

Each year in late summer the percentage of plants showing magnesium-deficiency symptoms was recorded, and a sample of twenty-four plants harvested from each of the magnesium treatments and analysed. All the magnesium fertilizers increased the concentration of magnesium in leaves, petioles and roots, and also decreased the number of plants showing deficiency symptoms.

The magnesium concentrations in plants grown without magnesium differed widely and were related both to the yield response to magnesium fertilizer and to the percentage of plants with deficiency symptoms. Both relationships showed a similar ‘transition zone’ from deficiency to adequate supply, for leaves this was 0·2–0·4% Mg, for petioles 0·1–0·2 Mg and for roots 0·075–0·125 % Mg in the dry matter.